diff --git a/test_app/apks/invalid.apk b/test_app/apks/invalid.apk
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/test_runner/src/main/kotlin/ftl/args/AndroidArgs.kt b/test_runner/src/main/kotlin/ftl/args/AndroidArgs.kt
index 16d3c21003..618033dd1d 100644
--- a/test_runner/src/main/kotlin/ftl/args/AndroidArgs.kt
+++ b/test_runner/src/main/kotlin/ftl/args/AndroidArgs.kt
@@ -70,9 +70,12 @@ class AndroidArgs(
     override val smartFlankGcsPath = flank.smartFlankGcsPath
     override val testTargetsAlwaysRun = cli?.testTargetsAlwaysRun ?: flank.testTargetsAlwaysRun
     override val filesToDownload = cli?.filesToDownload ?: flank.filesToDownload
+    override val disableSharding = cli?.disableSharding ?: flank.disableSharding
 
     // computed properties not specified in yaml
     override val testShardChunks: List<List<String>> by lazy {
+        if (disableSharding) return@lazy listOf(emptyList<String>())
+
         // Download test APK if necessary so it can be used to validate test methods
         var testLocalApk = testApk
         if (testApk.startsWith(FtlConstants.GCS_PREFIX)) {
@@ -168,6 +171,7 @@ ${devicesToString(devices)}
 ${listToString(filesToDownload)}
       test-targets-always-run:
 ${listToString(testTargetsAlwaysRun)}
+      disableSharding: $disableSharding
    """.trimIndent()
     }
 
diff --git a/test_runner/src/main/kotlin/ftl/args/IArgs.kt b/test_runner/src/main/kotlin/ftl/args/IArgs.kt
index 51912cdb09..654db94981 100644
--- a/test_runner/src/main/kotlin/ftl/args/IArgs.kt
+++ b/test_runner/src/main/kotlin/ftl/args/IArgs.kt
@@ -21,6 +21,7 @@ interface IArgs {
     val smartFlankGcsPath: String
     val testTargetsAlwaysRun: List<String>
     val filesToDownload: List<String>
+    val disableSharding: Boolean
 
     // computed property
     val testShardChunks: List<List<String>>
diff --git a/test_runner/src/main/kotlin/ftl/args/IosArgs.kt b/test_runner/src/main/kotlin/ftl/args/IosArgs.kt
index edacaa1dc7..4e7c0f727d 100644
--- a/test_runner/src/main/kotlin/ftl/args/IosArgs.kt
+++ b/test_runner/src/main/kotlin/ftl/args/IosArgs.kt
@@ -55,6 +55,7 @@ class IosArgs(
     override val smartFlankGcsPath = flank.smartFlankGcsPath
     override val testTargetsAlwaysRun = cli?.testTargetsAlwaysRun ?: flank.testTargetsAlwaysRun
     override val filesToDownload = cli?.filesToDownload ?: flank.filesToDownload
+    override val disableSharding = cli?.disableSharding ?: flank.disableSharding
 
     private val iosFlank = iosFlankYml.flank
     val testTargets = cli?.testTargets ?: iosFlank.testTargets
@@ -133,6 +134,7 @@ ${listToString(filesToDownload)}
       # iOS flank
       test-targets:
 ${listToString(testTargets)}
+      disableSharding: $disableSharding
     """.trimIndent()
     }
 
diff --git a/test_runner/src/main/kotlin/ftl/args/yml/FlankYml.kt b/test_runner/src/main/kotlin/ftl/args/yml/FlankYml.kt
index 2a39f22659..a36774fbe0 100644
--- a/test_runner/src/main/kotlin/ftl/args/yml/FlankYml.kt
+++ b/test_runner/src/main/kotlin/ftl/args/yml/FlankYml.kt
@@ -12,6 +12,7 @@ class FlankYmlParams(
     val shardTime: Int = -1,
     val repeatTests: Int = 1,
     val smartFlankGcsPath: String = "",
+    val disableSharding: Boolean = false,
 
     @field:JsonProperty("test-targets-always-run")
     val testTargetsAlwaysRun: List<String> = emptyList(),
@@ -21,7 +22,7 @@ class FlankYmlParams(
 ) {
     companion object : IYmlKeys {
         override val keys = listOf(
-            "testShards", "shardTime", "repeatTests", "smartFlankGcsPath", "test-targets-always-run", "files-to-download"
+            "testShards", "shardTime", "repeatTests", "smartFlankGcsPath", "disableSharding", "test-targets-always-run", "files-to-download"
         )
     }
 
diff --git a/test_runner/src/main/kotlin/ftl/args/yml/GcloudYml.kt b/test_runner/src/main/kotlin/ftl/args/yml/GcloudYml.kt
index 1034a4abf3..4f4235cd97 100644
--- a/test_runner/src/main/kotlin/ftl/args/yml/GcloudYml.kt
+++ b/test_runner/src/main/kotlin/ftl/args/yml/GcloudYml.kt
@@ -38,7 +38,8 @@ class GcloudYmlParams(
 ) {
     companion object : IYmlKeys {
         override val keys =
-            listOf("results-bucket", "results-dir", "record-video", "timeout", "async", "project", "results-history-name", "flaky-test-attempts")
+            listOf("results-bucket", "results-dir", "record-video", "timeout", "async", "project",
+                "results-history-name", "flaky-test-attempts")
     }
 
     init {
diff --git a/test_runner/src/main/kotlin/ftl/cli/firebase/test/android/AndroidRunCommand.kt b/test_runner/src/main/kotlin/ftl/cli/firebase/test/android/AndroidRunCommand.kt
index 2bcb570f54..a1033a2496 100644
--- a/test_runner/src/main/kotlin/ftl/cli/firebase/test/android/AndroidRunCommand.kt
+++ b/test_runner/src/main/kotlin/ftl/cli/firebase/test/android/AndroidRunCommand.kt
@@ -251,6 +251,12 @@ class AndroidRunCommand : Runnable {
     )
     var filesToDownload: List<String>? = null
 
+    @Option(
+        names = ["--disable-sharding"],
+        description = ["Disable sharding."]
+    )
+    var disableSharding: Boolean? = null
+
     @Option(
         names = ["--results-dir"],
         description = [
diff --git a/test_runner/src/main/kotlin/ftl/cli/firebase/test/ios/IosRunCommand.kt b/test_runner/src/main/kotlin/ftl/cli/firebase/test/ios/IosRunCommand.kt
index 280d24eddc..f0374c71e6 100644
--- a/test_runner/src/main/kotlin/ftl/cli/firebase/test/ios/IosRunCommand.kt
+++ b/test_runner/src/main/kotlin/ftl/cli/firebase/test/ios/IosRunCommand.kt
@@ -142,6 +142,12 @@ class IosRunCommand : Runnable {
     )
     var filesToDownload: List<String>? = null
 
+    @Option(
+        names = ["--disable-sharding"],
+        description = ["Disable sharding."]
+    )
+    var disableSharding: Boolean? = null
+
     @Option(
         names = ["--test"],
         description = ["The path to the test package (a zip file containing the iOS app " +
diff --git a/test_runner/src/main/kotlin/ftl/gc/GcIosTestMatrix.kt b/test_runner/src/main/kotlin/ftl/gc/GcIosTestMatrix.kt
index 5f24af7cd4..df804a7ea2 100644
--- a/test_runner/src/main/kotlin/ftl/gc/GcIosTestMatrix.kt
+++ b/test_runner/src/main/kotlin/ftl/gc/GcIosTestMatrix.kt
@@ -43,8 +43,8 @@ object GcIosTestMatrix {
         val methods = args.testShardChunks.elementAt(testShardsIndex)
 
         // Parameterized tests on iOS don't shard correctly.
-        // Avoid changing Xctestrun file when test shards is 1.
-        val generatedXctestrun = if (args.testShards == 1) {
+        // Avoid changing Xctestrun file when disableSharding is on.
+        val generatedXctestrun = if (args.disableSharding) {
             xcTestParsed.toByteArray()
         } else {
             Xctestrun.rewrite(xcTestParsed, methods)
diff --git a/test_runner/src/test/kotlin/ftl/args/AndroidArgsTest.kt b/test_runner/src/test/kotlin/ftl/args/AndroidArgsTest.kt
index cafb841519..e525a9ee69 100644
--- a/test_runner/src/test/kotlin/ftl/args/AndroidArgsTest.kt
+++ b/test_runner/src/test/kotlin/ftl/args/AndroidArgsTest.kt
@@ -18,6 +18,7 @@ import picocli.CommandLine
 class AndroidArgsTest {
     private val empty = emptyList<String>()
     private val appApk = "../test_app/apks/app-debug.apk"
+    private val invalidApk = "../test_app/apks/invalid.apk"
     private val testApk = "../test_app/apks/app-debug-androidTest.apk"
     private val testErrorApk = "../test_app/apks/error-androidTest.apk"
     private val appApkAbsolutePath = appApk.absolutePath()
@@ -67,6 +68,7 @@ class AndroidArgsTest {
           test-targets-always-run:
             - class example.Test#grantPermission
             - class example.Test#grantPermission2
+          disableSharding: true
       """
 
     @Rule
@@ -168,6 +170,7 @@ class AndroidArgsTest {
                     "class example.Test#grantPermission2"
                 )
             )
+            assert(disableSharding, true)
         }
     }
 
@@ -222,6 +225,7 @@ AndroidArgs
       test-targets-always-run:
         - class example.Test#grantPermission
         - class example.Test#grantPermission2
+      disableSharding: true
 """.trimIndent()
         )
     }
@@ -261,6 +265,7 @@ AndroidArgs
             assert(repeatTests, 1)
             assert(filesToDownload, empty)
             assert(testTargetsAlwaysRun, empty)
+            assert(disableSharding, false)
         }
     }
 
@@ -300,6 +305,28 @@ AndroidArgs
         assertThat(androidArgs.testApk).isEqualTo(testApkAbsolutePath)
     }
 
+    @Test
+    fun `disableSharding allows using invalid apk`() {
+        val yaml = """
+        gcloud:
+          app: $invalidApk
+          test: $invalidApk
+        flank:
+          disableSharding: true
+      """
+        AndroidArgs.load(yaml).testShardChunks
+    }
+
+    @Test(expected = RuntimeException::class)
+    fun `Invalid apk throws`() {
+        val yaml = """
+        gcloud:
+          app: $invalidApk
+          test: $invalidApk
+      """
+        AndroidArgs.load(yaml).testShardChunks
+    }
+
     @Test
     fun cli_app() {
         val cli = AndroidRunCommand()
@@ -673,7 +700,7 @@ AndroidArgs
     }
 
     @Test
-    fun `cli shardTime`() {
+    fun cli_shardTime() {
         val cli = AndroidRunCommand()
         CommandLine(cli).parse("--shard-time=3")
 
@@ -689,6 +716,23 @@ AndroidArgs
         assertThat(AndroidArgs.load(yaml, cli).shardTime).isEqualTo(3)
     }
 
+    @Test
+    fun cli_disableSharding() {
+        val cli = AndroidRunCommand()
+        CommandLine(cli).parse("--disable-sharding")
+
+        val yaml = """
+        gcloud:
+          app: $appApk
+          test: $testApk
+
+        flank:
+          disableSharding: false
+      """
+        assertThat(AndroidArgs.load(yaml).disableSharding).isEqualTo(false)
+        assertThat(AndroidArgs.load(yaml, cli).disableSharding).isEqualTo(true)
+    }
+
     @Test
     fun cli_repeatTests() {
         val cli = AndroidRunCommand()
diff --git a/test_runner/src/test/kotlin/ftl/args/IosArgsTest.kt b/test_runner/src/test/kotlin/ftl/args/IosArgsTest.kt
index 469f6e27d5..4e6ad0b935 100644
--- a/test_runner/src/test/kotlin/ftl/args/IosArgsTest.kt
+++ b/test_runner/src/test/kotlin/ftl/args/IosArgsTest.kt
@@ -63,6 +63,7 @@ class IosArgsTest {
           test-targets:
             - b/testBasicSelection
             - b/testBasicSelection2
+          disableSharding: true
         """
 
     @Rule
@@ -128,6 +129,7 @@ class IosArgsTest {
             assert(testTargets, listOf("b/testBasicSelection", "b/testBasicSelection2"))
 
             assert(flakyTestAttempts, 4)
+            assert(disableSharding, true)
         }
     }
 
@@ -174,6 +176,7 @@ IosArgs
       test-targets:
         - b/testBasicSelection
         - b/testBasicSelection2
+      disableSharding: true
 """.trimIndent()
         )
     }
@@ -208,6 +211,7 @@ IosArgs
             assert(repeatTests, 1)
             assert(testTargetsAlwaysRun, emptyList<String>())
             assert(filesToDownload, emptyList<String>())
+            assert(disableSharding, false)
 
             // IosFlankYml
             assert(testTargets, empty)
@@ -377,7 +381,7 @@ IosArgs
     }
 
     @Test
-    fun `cli shardTime`() {
+    fun cli_shardTime() {
         val cli = IosRunCommand()
         CommandLine(cli).parse("--shard-time=3")
 
@@ -393,6 +397,23 @@ IosArgs
         assertThat(IosArgs.load(yaml, cli).shardTime).isEqualTo(3)
     }
 
+    @Test
+    fun cli_disableSharding() {
+        val cli = IosRunCommand()
+        CommandLine(cli).parse("--disable-sharding")
+
+        val yaml = """
+        gcloud:
+          test: $testPath
+          xctestrun-file: $xctestrunFile
+
+        flank:
+          disableSharding: false
+      """
+        assertThat(IosArgs.load(yaml).disableSharding).isEqualTo(false)
+        assertThat(IosArgs.load(yaml, cli).disableSharding).isEqualTo(true)
+    }
+
     @Test
     fun cli_repeatTests() {
         val cli = IosRunCommand()
diff --git a/test_runner/src/test/kotlin/ftl/cli/firebase/test/android/AndroidRunCommandTest.kt b/test_runner/src/test/kotlin/ftl/cli/firebase/test/android/AndroidRunCommandTest.kt
index b8f9504477..efaff3944c 100644
--- a/test_runner/src/test/kotlin/ftl/cli/firebase/test/android/AndroidRunCommandTest.kt
+++ b/test_runner/src/test/kotlin/ftl/cli/firebase/test/android/AndroidRunCommandTest.kt
@@ -84,6 +84,7 @@ class AndroidRunCommandTest {
         assertThat(cmd.filesToDownload).isNull()
         assertThat(cmd.resultsDir).isNull()
         assertThat(cmd.flakyTestAttempts).isNull()
+        assertThat(cmd.disableSharding).isNull()
     }
 
     @Test
@@ -300,4 +301,12 @@ class AndroidRunCommandTest {
 
         assertThat(cmd.shardTime).isEqualTo(99)
     }
+
+    @Test
+    fun `disableSharding parse`() {
+        val cmd = AndroidRunCommand()
+        CommandLine(cmd).parse("--disable-sharding")
+
+        assertThat(cmd.disableSharding).isEqualTo(true)
+    }
 }
diff --git a/test_runner/src/test/kotlin/ftl/cli/firebase/test/ios/IosRunCommandTest.kt b/test_runner/src/test/kotlin/ftl/cli/firebase/test/ios/IosRunCommandTest.kt
index a7a3fc1680..07a93d805f 100644
--- a/test_runner/src/test/kotlin/ftl/cli/firebase/test/ios/IosRunCommandTest.kt
+++ b/test_runner/src/test/kotlin/ftl/cli/firebase/test/ios/IosRunCommandTest.kt
@@ -71,6 +71,7 @@ class IosRunCommandTest {
         assertThat(cmd.testTargetsAlwaysRun).isNull()
         assertThat(cmd.testTargets).isNull()
         assertThat(cmd.filesToDownload).isNull()
+        assertThat(cmd.disableSharding).isNull()
         assertThat(cmd.test).isNull()
         assertThat(cmd.xctestrunFile).isNull()
         assertThat(cmd.xcodeVersion).isNull()
@@ -234,4 +235,12 @@ class IosRunCommandTest {
 
         assertThat(cmd.shardTime).isEqualTo(99)
     }
+
+    @Test
+    fun `disableShard parse`() {
+        val cmd = IosRunCommand()
+        CommandLine(cmd).parse("--disable-sharding")
+
+        assertThat(cmd.disableSharding).isEqualTo(true)
+    }
 }