diff --git a/Vonage.Test/SimSwap/Authenticate/AuthenticateRequest.cs b/Vonage.Test/SimSwap/Authenticate/AuthenticateRequest.cs
index 0c9a1333..34e37d4d 100644
--- a/Vonage.Test/SimSwap/Authenticate/AuthenticateRequest.cs
+++ b/Vonage.Test/SimSwap/Authenticate/AuthenticateRequest.cs
@@ -16,13 +16,6 @@ public void Parse_ShouldReturnFailure_GivenNumberIsNullOrWhitespace(string value
         Vonage.SimSwap.Authenticate.AuthenticateRequest.Parse(value).Should()
             .BeFailure(ResultFailure.FromErrorMessage("Number cannot be null or whitespace."));
     
-    [Fact]
-    public void Parse_ShouldReturnNumberWithPlusIndicator() =>
-        Vonage.SimSwap.Authenticate.AuthenticateRequest.Parse("123456789")
-            .Map(number => number.PhoneNumber.NumberWithInternationalIndicator)
-            .Should()
-            .BeSuccess("+123456789");
-    
     [Fact]
     public void Parse_ShouldReturnFailure_GivenNumberContainsNonDigits() =>
         Vonage.SimSwap.Authenticate.AuthenticateRequest.Parse("1234567abc123").Should()
@@ -41,24 +34,13 @@ public void Parse_ShouldReturnFailure_GivenNumberLengthIsLowerThan15() =>
     [Theory]
     [InlineData("1234567", "1234567")]
     [InlineData("123456789012345", "123456789012345")]
-    public void Parse_ShouldReturnSuccess_GivenNumberIsValid(string value, string expected) =>
-        Vonage.SimSwap.Authenticate.AuthenticateRequest.Parse(value).Map(number => number.PhoneNumber.Number).Should()
-            .BeSuccess(expected);
-    
-    [Theory]
     [InlineData("+1234567890", "1234567890")]
     [InlineData("+123456789012345", "123456789012345")]
     [InlineData("+++1234567890", "1234567890")]
-    public void Parse_ShouldReturnSuccess_GivenNumberStartWithPlus(string value, string expected) =>
+    public void Parse_ShouldReturnSuccess_GivenNumberIsValid(string value, string expected) =>
         Vonage.SimSwap.Authenticate.AuthenticateRequest.Parse(value).Map(number => number.PhoneNumber.Number).Should()
             .BeSuccess(expected);
     
-    [Fact]
-    public void ToString_ShouldReturnNumber() =>
-        Vonage.SimSwap.Authenticate.AuthenticateRequest.Parse("123456789").Map(number => number.PhoneNumber.ToString())
-            .Should()
-            .BeSuccess("123456789");
-    
     [Fact]
     public void BuildAuthorizeRequest()
     {
diff --git a/Vonage.Test/SimSwap/Authenticate/AuthenticateResponseTest.cs b/Vonage.Test/SimSwap/Authenticate/AuthenticateResponseTest.cs
new file mode 100644
index 00000000..477f3696
--- /dev/null
+++ b/Vonage.Test/SimSwap/Authenticate/AuthenticateResponseTest.cs
@@ -0,0 +1,17 @@
+using System.Net.Http.Headers;
+using FluentAssertions;
+using Vonage.SimSwap.Authenticate;
+using Xunit;
+
+namespace Vonage.Test.SimSwap.Authenticate;
+
+[Trait("Category", "Request")]
+public class AuthenticateResponseTest
+{
+    [Fact]
+    public void BuildAuthenticationHeader_ShouldReturnBearerAuth() =>
+        new AuthenticateResponse("123456789")
+            .BuildAuthenticationHeader()
+            .Should()
+            .Be(new AuthenticationHeaderValue("Bearer", "123456789"));
+}
\ No newline at end of file
diff --git a/Vonage.Test/SimSwap/Check/Data/ShouldDeserializeAccessToken-response.json b/Vonage.Test/SimSwap/Check/Data/ShouldDeserializeAccessToken-response.json
new file mode 100644
index 00000000..73ab58da
--- /dev/null
+++ b/Vonage.Test/SimSwap/Check/Data/ShouldDeserializeAccessToken-response.json
@@ -0,0 +1,5 @@
+{
+  "access_token": "ABCDEFG",
+  "token_type": "Bearer",
+  "expires_in": 3600
+}
\ No newline at end of file
diff --git a/Vonage.Test/SimSwap/Check/Data/ShouldDeserializeAuthorize-response.json b/Vonage.Test/SimSwap/Check/Data/ShouldDeserializeAuthorize-response.json
new file mode 100644
index 00000000..7b424919
--- /dev/null
+++ b/Vonage.Test/SimSwap/Check/Data/ShouldDeserializeAuthorize-response.json
@@ -0,0 +1,5 @@
+{
+  "auth_req_id": "123456789",
+  "expires_in": "120",
+  "interval": "2"
+}
\ No newline at end of file
diff --git a/Vonage.Test/SimSwap/Check/Data/ShouldDeserializeCheck-response.json b/Vonage.Test/SimSwap/Check/Data/ShouldDeserializeCheck-response.json
new file mode 100644
index 00000000..d7ea7844
--- /dev/null
+++ b/Vonage.Test/SimSwap/Check/Data/ShouldDeserializeCheck-response.json
@@ -0,0 +1,3 @@
+{
+  "swapped": true
+}
\ No newline at end of file
diff --git a/Vonage.Test/SimSwap/Check/Data/ShouldSerialize-request.json b/Vonage.Test/SimSwap/Check/Data/ShouldSerialize-request.json
new file mode 100644
index 00000000..1709c701
--- /dev/null
+++ b/Vonage.Test/SimSwap/Check/Data/ShouldSerialize-request.json
@@ -0,0 +1,4 @@
+{
+  "phoneNumber": "346661113334",
+  "maxAge": 240
+}
\ No newline at end of file
diff --git a/Vonage.Test/SimSwap/Check/Data/ShouldSerializeWithPeriod-request.json b/Vonage.Test/SimSwap/Check/Data/ShouldSerializeWithPeriod-request.json
new file mode 100644
index 00000000..687bc593
--- /dev/null
+++ b/Vonage.Test/SimSwap/Check/Data/ShouldSerializeWithPeriod-request.json
@@ -0,0 +1,4 @@
+{
+  "phoneNumber": "346661113334",
+  "maxAge": 15
+}
\ No newline at end of file
diff --git a/Vonage.Test/SimSwap/Check/E2ETest.cs b/Vonage.Test/SimSwap/Check/E2ETest.cs
new file mode 100644
index 00000000..2538f22f
--- /dev/null
+++ b/Vonage.Test/SimSwap/Check/E2ETest.cs
@@ -0,0 +1,68 @@
+using System.Net;
+using System.Threading.Tasks;
+using Vonage.SimSwap.Check;
+using Vonage.Test.Common.Extensions;
+using WireMock.ResponseBuilders;
+using Xunit;
+
+namespace Vonage.Test.SimSwap.Check;
+
+[Trait("Category", "E2E")]
+public class E2ETest : E2EBase
+{
+    public E2ETest() : base(typeof(E2ETest).Namespace)
+    {
+    }
+    
+    [Fact]
+    public async Task CheckAsync()
+    {
+        this.SetupAuthorization();
+        this.SetupToken();
+        this.SetupSimSwap(nameof(SerializationTest.ShouldSerialize));
+        await this.Helper.VonageClient.SimSwapClient
+            .CheckAsync(CheckRequest.Build().WithPhoneNumber("346661113334").Create())
+            .Should()
+            .BeSuccessAsync(true);
+    }
+    
+    [Fact]
+    public async Task CheckAsyncWithPeriod()
+    {
+        this.SetupAuthorization();
+        this.SetupToken();
+        this.SetupSimSwap(nameof(SerializationTest.ShouldSerializeWithPeriod));
+        await this.Helper.VonageClient.SimSwapClient
+            .CheckAsync(CheckRequest.Build().WithPhoneNumber("346661113334").WithPeriod(15).Create())
+            .Should()
+            .BeSuccessAsync(true);
+    }
+    
+    private void SetupSimSwap(string expectedOutput) =>
+        this.Helper.Server.Given(WireMock.RequestBuilders.Request.Create()
+                .WithPath("/camara/sim-swap/v040/check")
+                .WithHeader("Authorization", "Bearer ABCDEFG")
+                .WithBody(this.Serialization.GetRequestJson(expectedOutput))
+                .UsingPost())
+            .RespondWith(Response.Create().WithStatusCode(HttpStatusCode.OK)
+                .WithBody(this.Serialization.GetResponseJson(nameof(SerializationTest.ShouldDeserializeCheck))));
+    
+    private void SetupToken() =>
+        this.Helper.Server.Given(WireMock.RequestBuilders.Request.Create()
+                .WithPath("/oauth2/token")
+                .WithHeader("Authorization", this.Helper.ExpectedAuthorizationHeaderValue)
+                .WithBody("auth_req_id=123456789&grant_type=urn:openid:params:grant-type:ciba")
+                .UsingPost())
+            .RespondWith(Response.Create().WithStatusCode(HttpStatusCode.OK)
+                .WithBody(this.Serialization.GetResponseJson(nameof(SerializationTest.ShouldDeserializeAccessToken))));
+    
+    private void SetupAuthorization() =>
+        this.Helper.Server.Given(WireMock.RequestBuilders.Request.Create()
+                .WithPath("/oauth2/bc-authorize")
+                .WithHeader("Authorization", this.Helper.ExpectedAuthorizationHeaderValue)
+                .WithBody(
+                    "login_hint=tel:%2B346661113334&scope=openid+dpv%3AFraudPreventionAndDetection%23check-sim-swap")
+                .UsingPost())
+            .RespondWith(Response.Create().WithStatusCode(HttpStatusCode.OK)
+                .WithBody(this.Serialization.GetResponseJson(nameof(SerializationTest.ShouldDeserializeAuthorize))));
+}
\ No newline at end of file
diff --git a/Vonage.Test/SimSwap/Check/RequestBuilderTest.cs b/Vonage.Test/SimSwap/Check/RequestBuilderTest.cs
new file mode 100644
index 00000000..7d5f717b
--- /dev/null
+++ b/Vonage.Test/SimSwap/Check/RequestBuilderTest.cs
@@ -0,0 +1,102 @@
+using Vonage.Common.Failures;
+using Vonage.SimSwap.Check;
+using Vonage.Test.Common.Extensions;
+using Xunit;
+
+namespace Vonage.Test.SimSwap.Check;
+
+[Trait("Category", "Request")]
+public class RequestBuilderTest
+{
+    [Theory]
+    [InlineData("")]
+    [InlineData(" ")]
+    [InlineData(null)]
+    public void Build_ShouldReturnFailure_GivenNumberIsNullOrWhitespace(string value) =>
+        CheckRequest.Build()
+            .WithPhoneNumber(value)
+            .Create()
+            .Should()
+            .BeFailure(ResultFailure.FromErrorMessage("Number cannot be null or whitespace."));
+    
+    [Fact]
+    public void Build_ShouldReturnFailure_GivenNumberContainsNonDigits() =>
+        CheckRequest.Build()
+            .WithPhoneNumber("1234567abc123")
+            .Create()
+            .Should()
+            .BeFailure(ResultFailure.FromErrorMessage("Number can only contain digits."));
+    
+    [Fact]
+    public void Build_ShouldReturnFailure_GivenNumberLengthIsHigherThan7() =>
+        CheckRequest.Build()
+            .WithPhoneNumber("123456")
+            .Create()
+            .Should()
+            .BeFailure(ResultFailure.FromErrorMessage("Number length cannot be lower than 7."));
+    
+    [Fact]
+    public void Build_ShouldReturnFailure_GivenNumberLengthIsLowerThan15() =>
+        CheckRequest.Build()
+            .WithPhoneNumber("1234567890123456")
+            .Create()
+            .Should()
+            .BeFailure(ResultFailure.FromErrorMessage("Number length cannot be higher than 15."));
+    
+    [Theory]
+    [InlineData("1234567", "1234567")]
+    [InlineData("123456789012345", "123456789012345")]
+    [InlineData("+1234567890", "1234567890")]
+    [InlineData("+123456789012345", "123456789012345")]
+    [InlineData("+++1234567890", "1234567890")]
+    public void Build_ShouldSetPhoneNumber_GivenNumberIsValid(string value, string expected) =>
+        CheckRequest.Build()
+            .WithPhoneNumber(value)
+            .Create()
+            .Map(number => number.PhoneNumber.Number)
+            .Should()
+            .BeSuccess(expected);
+    
+    [Theory]
+    [InlineData(1)]
+    [InlineData(2400)]
+    public void Build_ShouldSetPeriod(int value) =>
+        CheckRequest.Build()
+            .WithPhoneNumber("1234567")
+            .WithPeriod(value)
+            .Create()
+            .Map(number => number.Period)
+            .Should()
+            .BeSuccess(value);
+    
+    [Fact]
+    public void Build_ShouldSetPeriodToDefault_GivenPeriodIsNotSet() =>
+        CheckRequest.Build()
+            .WithPhoneNumber("1234567")
+            .Create()
+            .Map(number => number.Period)
+            .Should()
+            .BeSuccess(240);
+    
+    [Theory]
+    [InlineData(0)]
+    [InlineData(-1)]
+    public void Build_ShouldReturnFailure_GivenPeriodIsLowerThan15(int incorrectValue) =>
+        CheckRequest.Build()
+            .WithPhoneNumber("1234567")
+            .WithPeriod(incorrectValue)
+            .Create()
+            .Should()
+            .BeParsingFailure("Period cannot be lower than 1.");
+    
+    [Theory]
+    [InlineData(2401)]
+    [InlineData(2402)]
+    public void Build_ShouldReturnFailure_GivenPeriodIsHigherThan2400(int incorrectValue) =>
+        CheckRequest.Build()
+            .WithPhoneNumber("1234567")
+            .WithPeriod(incorrectValue)
+            .Create()
+            .Should()
+            .BeParsingFailure("Period cannot be higher than 2400.");
+}
\ No newline at end of file
diff --git a/Vonage.Test/SimSwap/Check/RequestTest.cs b/Vonage.Test/SimSwap/Check/RequestTest.cs
new file mode 100644
index 00000000..05cb9831
--- /dev/null
+++ b/Vonage.Test/SimSwap/Check/RequestTest.cs
@@ -0,0 +1,18 @@
+using Vonage.SimSwap.Check;
+using Vonage.Test.Common.Extensions;
+using Xunit;
+
+namespace Vonage.Test.SimSwap.Check;
+
+[Trait("Category", "Request")]
+public class RequestTest
+{
+    [Fact]
+    public void GetEndpointPath_ShouldReturnApiEndpoint() =>
+        CheckRequest.Build()
+            .WithPhoneNumber("123456789")
+            .Create()
+            .Map(request => request.GetEndpointPath())
+            .Should()
+            .BeSuccess("camara/sim-swap/v040/check");
+}
\ No newline at end of file
diff --git a/Vonage.Test/SimSwap/Check/SerializationTest.cs b/Vonage.Test/SimSwap/Check/SerializationTest.cs
new file mode 100644
index 00000000..7eb0f51d
--- /dev/null
+++ b/Vonage.Test/SimSwap/Check/SerializationTest.cs
@@ -0,0 +1,59 @@
+using Vonage.Serialization;
+using Vonage.SimSwap.Authenticate;
+using Vonage.SimSwap.Check;
+using Vonage.Test.Common;
+using Vonage.Test.Common.Extensions;
+using Xunit;
+
+namespace Vonage.Test.SimSwap.Check;
+
+[Trait("Category", "Serialization")]
+public class SerializationTest
+{
+    private readonly SerializationTestHelper helper = new SerializationTestHelper(
+        typeof(SerializationTest).Namespace,
+        JsonSerializerBuilder.BuildWithSnakeCase());
+    
+    [Fact]
+    public void ShouldDeserializeAuthorize() => this.helper.Serializer
+        .DeserializeObject<AuthorizeResponse>(this.helper.GetResponseJson())
+        .Should()
+        .BeSuccess(GetExpectedAuthorizeResponse());
+    
+    [Fact]
+    public void ShouldDeserializeAccessToken() => this.helper.Serializer
+        .DeserializeObject<GetTokenResponse>(this.helper.GetResponseJson())
+        .Should()
+        .BeSuccess(GetExpectedTokenResponse());
+    
+    [Fact]
+    public void ShouldDeserializeCheck() => this.helper.Serializer
+        .DeserializeObject<CheckResponse>(this.helper.GetResponseJson())
+        .Should()
+        .BeSuccess(GetExpectedResponse());
+    
+    [Fact]
+    public void ShouldSerialize() =>
+        CheckRequest.Build()
+            .WithPhoneNumber("346661113334")
+            .Create()
+            .GetStringContent()
+            .Should()
+            .BeSuccess(this.helper.GetRequestJson());
+    
+    [Fact]
+    public void ShouldSerializeWithPeriod() =>
+        CheckRequest.Build()
+            .WithPhoneNumber("346661113334")
+            .WithPeriod(15)
+            .Create()
+            .GetStringContent()
+            .Should()
+            .BeSuccess(this.helper.GetRequestJson());
+    
+    private static AuthorizeResponse GetExpectedAuthorizeResponse() => new AuthorizeResponse("123456789", "120", "2");
+    
+    private static GetTokenResponse GetExpectedTokenResponse() => new GetTokenResponse("ABCDEFG", "Bearer", 3600);
+    
+    private static CheckResponse GetExpectedResponse() => new CheckResponse(true);
+}
\ No newline at end of file
diff --git a/Vonage.Test/Vonage.Test.csproj b/Vonage.Test/Vonage.Test.csproj
index d9279e5b..758bb54a 100644
--- a/Vonage.Test/Vonage.Test.csproj
+++ b/Vonage.Test/Vonage.Test.csproj
@@ -47,7 +47,6 @@
     </ItemGroup>
 
     <ItemGroup>
-        <Folder Include="SimSwap\Check\"/>
         <None Update="Data\NccoTests\TestRecord-request.json">
             <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
         </None>
@@ -1108,6 +1107,21 @@
         <None Update="SimSwap\Authenticate\Data\ShouldDeserializeAccessToken-response.json">
             <CopyToOutputDirectory>Always</CopyToOutputDirectory>
         </None>
+        <None Update="SimSwap\Check\Data\ShouldDeserializeAuthorize-response.json">
+            <CopyToOutputDirectory>Always</CopyToOutputDirectory>
+        </None>
+        <None Update="SimSwap\Check\Data\ShouldDeserializeAccessToken-response.json">
+            <CopyToOutputDirectory>Always</CopyToOutputDirectory>
+        </None>
+        <None Update="SimSwap\Check\Data\ShouldDeserializeCheck-response.json">
+            <CopyToOutputDirectory>Always</CopyToOutputDirectory>
+        </None>
+        <None Update="SimSwap\Check\Data\ShouldSerialize-request.json">
+            <CopyToOutputDirectory>Always</CopyToOutputDirectory>
+        </None>
+        <None Update="SimSwap\Check\Data\ShouldSerializeWithPeriod-request.json">
+            <CopyToOutputDirectory>Always</CopyToOutputDirectory>
+        </None>
     </ItemGroup>
     <Target Name="PreBuild" BeforeTargets="PreBuildEvent">
         <Exec Command="node ../.scripts/init.js"/>
diff --git a/Vonage/Common/Client/VonageHttpClient.cs b/Vonage/Common/Client/VonageHttpClient.cs
index 4508629f..314b9a77 100644
--- a/Vonage/Common/Client/VonageHttpClient.cs
+++ b/Vonage/Common/Client/VonageHttpClient.cs
@@ -16,6 +16,7 @@ public class VonageHttpClient
     private readonly HttpClient client;
     private readonly IJsonSerializer jsonSerializer;
     private readonly Result<HttpClientOptions> requestOptions;
+    private readonly string userAgent;
     
     /// <summary>
     ///     Creates a custom Http Client for Vonage purposes.
@@ -26,11 +27,16 @@ public VonageHttpClient(VonageHttpClientConfiguration configuration, IJsonSerial
     {
         this.client = configuration.HttpClient;
         this.jsonSerializer = serializer;
+        this.userAgent = configuration.UserAgent;
         this.requestOptions = configuration.AuthenticationHeader
             .Map(header =>
-                new HttpClientOptions(header, UserAgentProvider.GetFormattedUserAgent(configuration.UserAgent)));
+                new HttpClientOptions(header, UserAgentProvider.GetFormattedUserAgent(this.userAgent)));
     }
     
+    internal VonageHttpClient WithDifferentHeader(Result<AuthenticationHeaderValue> header) =>
+        new VonageHttpClient(new VonageHttpClientConfiguration(this.client, header, this.userAgent),
+            this.jsonSerializer);
+    
     /// <summary>
     ///     Sends a HttpRequest.
     /// </summary>
diff --git a/Vonage/SimSwap/Authenticate/AuthenticateResponse.cs b/Vonage/SimSwap/Authenticate/AuthenticateResponse.cs
index 4e95dd51..78f8a8ef 100644
--- a/Vonage/SimSwap/Authenticate/AuthenticateResponse.cs
+++ b/Vonage/SimSwap/Authenticate/AuthenticateResponse.cs
@@ -1,7 +1,16 @@
-namespace Vonage.SimSwap.Authenticate;
+using System.Net.Http.Headers;
+
+namespace Vonage.SimSwap.Authenticate;
 
 /// <summary>
 ///     Represents an authentication response.
 /// </summary>
 /// <param name="AccessToken">The access token.</param>
-public record AuthenticateResponse(string AccessToken);
\ No newline at end of file
+public record AuthenticateResponse(string AccessToken)
+{
+    /// <summary>
+    /// </summary>
+    /// <returns></returns>
+    public AuthenticationHeaderValue BuildAuthenticationHeader() =>
+        new AuthenticationHeaderValue("Bearer", this.AccessToken);
+}
\ No newline at end of file
diff --git a/Vonage/SimSwap/Check/CheckRequest.cs b/Vonage/SimSwap/Check/CheckRequest.cs
new file mode 100644
index 00000000..c0efdc2c
--- /dev/null
+++ b/Vonage/SimSwap/Check/CheckRequest.cs
@@ -0,0 +1,50 @@
+using System.Net.Http;
+using System.Text;
+using System.Text.Json.Serialization;
+using Vonage.Common;
+using Vonage.Common.Client;
+using Vonage.Common.Serialization;
+using Vonage.Serialization;
+
+namespace Vonage.SimSwap.Check;
+
+/// <summary>
+///     Represents a request to check if a SIM swap has been performed.
+/// </summary>
+public readonly struct CheckRequest : IVonageRequest
+
+{
+    /// <inheritdoc />
+    public HttpRequestMessage BuildRequestMessage() => VonageRequestBuilder
+        .Initialize(HttpMethod.Post, this.GetEndpointPath())
+        .WithContent(this.GetRequestContent())
+        .Build();
+    
+    private StringContent GetRequestContent() =>
+        new StringContent(JsonSerializerBuilder.BuildWithSnakeCase().SerializeObject(this), Encoding.UTF8,
+            "application/json");
+    
+    /// <inheritdoc />
+    public string GetEndpointPath() => "camara/sim-swap/v040/check";
+    
+    /// <summary>
+    ///     Subscriber number in E.164 format (starting with country code). Optionally prefixed with '+'.
+    /// </summary>
+    [JsonConverter(typeof(PhoneNumberJsonConverter))]
+    [JsonPropertyOrder(0)]
+    [JsonPropertyName("phoneNumber")]
+    public PhoneNumber PhoneNumber { get; internal init; }
+    
+    /// <summary>
+    ///     Period in hours to be checked for SIM swap.
+    /// </summary>
+    [JsonPropertyOrder(1)]
+    [JsonPropertyName("maxAge")]
+    public int Period { get; internal init; }
+    
+    /// <summary>
+    ///     Initializes a builder.
+    /// </summary>
+    /// <returns>The builder.</returns>
+    public static IBuilderForPhoneNumber Build() => new CheckRequestBuilder();
+}
\ No newline at end of file
diff --git a/Vonage/SimSwap/Check/CheckRequestBuilder.cs b/Vonage/SimSwap/Check/CheckRequestBuilder.cs
new file mode 100644
index 00000000..ecbe23fe
--- /dev/null
+++ b/Vonage/SimSwap/Check/CheckRequestBuilder.cs
@@ -0,0 +1,72 @@
+using Vonage.Common;
+using Vonage.Common.Client;
+using Vonage.Common.Monads;
+using Vonage.Common.Validation;
+
+namespace Vonage.SimSwap.Check;
+
+internal class CheckRequestBuilder : IBuilderForPhoneNumber, IBuilderForOptional
+{
+    private const int MaximumPeriod = 2400;
+    private const int MinimumPeriod = 1;
+    private const int DefaultPeriod = 240;
+    private string number;
+    private int period = DefaultPeriod;
+    
+    /// <inheritdoc />
+    public Result<CheckRequest> Create() =>
+        PhoneNumber.Parse(this.number)
+            .Map(phoneNumber => new CheckRequest
+            {
+                PhoneNumber = phoneNumber,
+                Period = this.period,
+            })
+            .Map(InputEvaluation<CheckRequest>.Evaluate)
+            .Bind(evaluation => evaluation.WithRules(VerifyAgeMinimumPeriod, VerifyMaximumPeriod));
+    
+    /// <inheritdoc />
+    public IVonageRequestBuilder<CheckRequest> WithPeriod(int value) => new CheckRequestBuilder
+    {
+        number = this.number,
+        period = value,
+    };
+    
+    /// <inheritdoc />
+    public IBuilderForOptional WithPhoneNumber(string value) => new CheckRequestBuilder
+    {
+        number = value,
+        period = this.period,
+    };
+    
+    private static Result<CheckRequest> VerifyAgeMinimumPeriod(CheckRequest request) =>
+        InputValidation.VerifyHigherOrEqualThan(request, request.Period, MinimumPeriod, nameof(request.Period));
+    
+    private static Result<CheckRequest> VerifyMaximumPeriod(CheckRequest request) =>
+        InputValidation.VerifyLowerOrEqualThan(request, request.Period, MaximumPeriod, nameof(request.Period));
+}
+
+/// <summary>
+///     Represents a builder for PhoneNumber.
+/// </summary>
+public interface IBuilderForPhoneNumber
+{
+    /// <summary>
+    ///     Sets the phone number on the builder.
+    /// </summary>
+    /// <param name="value">The phone number.</param>
+    /// <returns>The builder.</returns>
+    IBuilderForOptional WithPhoneNumber(string value);
+}
+
+/// <summary>
+///     Represents a builder for optional values.
+/// </summary>
+public interface IBuilderForOptional : IVonageRequestBuilder<CheckRequest>
+{
+    /// <summary>
+    ///     Sets the period on the builder.
+    /// </summary>
+    /// <param name="value">The period in hours to be checked for SIM swap.</param>
+    /// <returns>The builder.</returns>
+    IVonageRequestBuilder<CheckRequest> WithPeriod(int value);
+}
\ No newline at end of file
diff --git a/Vonage/SimSwap/Check/CheckResponse.cs b/Vonage/SimSwap/Check/CheckResponse.cs
new file mode 100644
index 00000000..8f4f859c
--- /dev/null
+++ b/Vonage/SimSwap/Check/CheckResponse.cs
@@ -0,0 +1,3 @@
+namespace Vonage.SimSwap.Check;
+
+internal record CheckResponse(bool Swapped);
\ No newline at end of file
diff --git a/Vonage/SimSwap/ISimSwapClient.cs b/Vonage/SimSwap/ISimSwapClient.cs
index 19937470..a0323189 100644
--- a/Vonage/SimSwap/ISimSwapClient.cs
+++ b/Vonage/SimSwap/ISimSwapClient.cs
@@ -1,6 +1,7 @@
 using System.Threading.Tasks;
 using Vonage.Common.Monads;
 using Vonage.SimSwap.Authenticate;
+using Vonage.SimSwap.Check;
 
 namespace Vonage.SimSwap;
 
@@ -15,4 +16,11 @@ public interface ISimSwapClient
     /// <param name="request">The request.</param>
     /// <returns>Success or Failure.</returns>
     Task<Result<AuthenticateResponse>> AuthenticateAsync(Result<AuthenticateRequest> request);
+    
+    /// <summary>
+    ///     Check if SIM swap has been performed during a past period.
+    /// </summary>
+    /// <param name="request">The request.</param>
+    /// <returns>Success or Failure.</returns>
+    Task<Result<bool>> CheckAsync(Result<CheckRequest> request);
 }
\ No newline at end of file
diff --git a/Vonage/SimSwap/SimSwapClient.cs b/Vonage/SimSwap/SimSwapClient.cs
index 7d7fc79e..a2329c36 100644
--- a/Vonage/SimSwap/SimSwapClient.cs
+++ b/Vonage/SimSwap/SimSwapClient.cs
@@ -1,8 +1,10 @@
-using System.Threading.Tasks;
+using System.Net.Http.Headers;
+using System.Threading.Tasks;
 using Vonage.Common.Client;
 using Vonage.Common.Monads;
 using Vonage.Serialization;
 using Vonage.SimSwap.Authenticate;
+using Vonage.SimSwap.Check;
 
 namespace Vonage.SimSwap;
 
@@ -21,6 +23,23 @@ public Task<Result<AuthenticateResponse>> AuthenticateAsync(Result<AuthenticateR
             .BindAsync(this.SendGetTokenRequest)
             .Map(BuildAuthenticateResponse);
     
+    /// <inheritdoc />
+    public async Task<Result<bool>> CheckAsync(Result<CheckRequest> request) =>
+        await request.BindAsync(this.AuthenticateCheckRequest)
+            .Map(BuildAuthenticationHeader)
+            .Map(this.BuildClientWithAuthenticationHeader)
+            .BindAsync(client => client.SendWithResponseAsync<CheckRequest, CheckResponse>(request))
+            .Map(response => response.Swapped);
+    
+    private VonageHttpClient BuildClientWithAuthenticationHeader(AuthenticationHeaderValue header) =>
+        this.vonageClient.WithDifferentHeader(header);
+    
+    private static AuthenticationHeaderValue BuildAuthenticationHeader(AuthenticateResponse authentication) =>
+        authentication.BuildAuthenticationHeader();
+    
+    private Task<Result<AuthenticateResponse>> AuthenticateCheckRequest(CheckRequest r) =>
+        this.AuthenticateAsync(AuthenticateRequest.Parse(r.PhoneNumber.NumberWithInternationalIndicator));
+    
     private static AuthenticateResponse BuildAuthenticateResponse(GetTokenResponse response) =>
         new AuthenticateResponse(response.AccessToken);