diff --git a/app/src/main/java/com/hiddenramblings/tagmo/amiibo/tagdata/AmiiboData.kt b/app/src/main/java/com/hiddenramblings/tagmo/amiibo/tagdata/AmiiboData.kt
index 8712f8992..3a8ad060e 100644
--- a/app/src/main/java/com/hiddenramblings/tagmo/amiibo/tagdata/AmiiboData.kt
+++ b/app/src/main/java/com/hiddenramblings/tagmo/amiibo/tagdata/AmiiboData.kt
@@ -205,6 +205,11 @@ open class AmiiboData : Parcelable {
         if (value < WRITE_COUNT_MIN_VALUE || value > WRITE_COUNT_MAX_VALUE) throw NumberFormatException()
     }
 
+    @Throws(StringIndexOutOfBoundsException::class)
+    fun checkSerialNumber(value: String) {
+        if (value.length < 18) throw StringIndexOutOfBoundsException()
+    }
+
     @set:Throws(NumberFormatException::class)
     var writeCount: Int
         get() = tagData.getShort(WRITE_COUNT_OFFSET).toInt() and 0xFFFF
diff --git a/app/src/main/java/com/hiddenramblings/tagmo/amiibo/tagdata/TagDataEditor.kt b/app/src/main/java/com/hiddenramblings/tagmo/amiibo/tagdata/TagDataEditor.kt
index f4d3fdb90..1c5eee6f0 100644
--- a/app/src/main/java/com/hiddenramblings/tagmo/amiibo/tagdata/TagDataEditor.kt
+++ b/app/src/main/java/com/hiddenramblings/tagmo/amiibo/tagdata/TagDataEditor.kt
@@ -218,7 +218,20 @@ class TagDataEditor : AppCompatActivity() {
                 onAppDataSwitchClicked(checked)
             }
         }
-        txtSerialNumber = findViewById(R.id.txtSerialNumber)
+        txtSerialNumber = findViewById<EditText>(R.id.txtSerialNumber).apply {
+            addTextChangedListener(object : TextWatcher {
+                override fun beforeTextChanged(charSequence: CharSequence, i: Int, i1: Int, i2: Int) {}
+                override fun onTextChanged(charSequence: CharSequence, i: Int, i1: Int, i2: Int) {}
+                override fun afterTextChanged(editable: Editable) {
+                    try {
+                        amiiboData.checkSerialNumber(editable.toString())
+                        txtSerialNumber.error = null
+                    } catch (e: Exception) {
+                        txtSerialNumber.error = getString(R.string.error_serial)
+                    }
+                }
+            })
+        }
         generateSerial = findViewById<AppCompatButton>(R.id.random_serial).apply {
             setOnClickListener {
                 txtSerialNumber.setText(Foomiibo.generateRandomUID().toHex())
@@ -954,7 +967,7 @@ class TagDataEditor : AppCompatActivity() {
 
     private fun loadSerialNumber() {
         txtSerialNumber.tag = txtSerialNumber.keyListener
-        txtSerialNumber.keyListener = null
+        // txtSerialNumber.keyListener = null
         val value = amiiboData.uID
         txtSerialNumber.setText(value.toHex())
     }
@@ -1839,4 +1852,4 @@ class TagDataEditor : AppCompatActivity() {
             .show()
         setResult(RESULT_OK, Intent(NFCIntent.ACTION_FIX_BANK_DATA))
     }
-}
\ No newline at end of file
+}
diff --git a/app/src/main/res/layout/activity_tag_data.xml b/app/src/main/res/layout/activity_tag_data.xml
index b1de8633f..73e72d348 100644
--- a/app/src/main/res/layout/activity_tag_data.xml
+++ b/app/src/main/res/layout/activity_tag_data.xml
@@ -335,6 +335,8 @@
                             android:id="@+id/txtSerialNumber"
                             android:importantForAutofill="no"
                             style="@style/TagEditor.EditSerial"
+                            android:maxLength="10"
+                            android:maxLines="1"
                             android:paddingLeft="6dp"
                             android:paddingRight="6dp"
                             tools:ignore="LabelFor,TextFields" />
@@ -438,4 +440,4 @@
                 android:padding="2dp" />
         </LinearLayout>
     </ScrollView>
-</LinearLayout>
\ No newline at end of file
+</LinearLayout>
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 97a155bd6..7bb772284 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -387,6 +387,7 @@
     <string name="error_tag_unavailable">NTAG215 connection cannot be established!</string>
     <string name="error_state">State error. Invalid action: %1$s</string>
     <string name="error_length">Must be 8 characters</string>
+    <string name="error_serial">Must be 18 characters</string>
     <string name="error_input">Invalid input</string>
     <string name="error_min_max">Must be between %1$d and %2$d</string>
     <string name="error_data_write">Error while writing main data (stage 1)</string>