diff --git a/src/libraries/System.Text.Json/tests/System.Text.Json.Tests/Serialization/ConvertersForUnsupportedTypesFunctionalTests.cs b/src/libraries/System.Text.Json/tests/System.Text.Json.Tests/Serialization/ConvertersForUnsupportedTypesFunctionalTests.cs
new file mode 100644
index 00000000000000..847a5cf8f50e86
--- /dev/null
+++ b/src/libraries/System.Text.Json/tests/System.Text.Json.Tests/Serialization/ConvertersForUnsupportedTypesFunctionalTests.cs
@@ -0,0 +1,119 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Collections.Generic;
+using System.Globalization;
+using System.Numerics;
+using Xunit;
+
+namespace System.Text.Json.Serialization.Tests
+{
+    public static class ConvertersForUnsupportedTypesFunctionalTests
+    {
+        [Theory]
+        [MemberData(nameof(GetTestData))]
+        public static void RoundtripValues<T>(string expectedValueAsString, T value)
+        {
+            JsonSerializerOptions options = new()
+            {
+                Converters = { new Int128Converter(), new UInt128Converter(), new HalfConverter(), new BigIntegerConverter() }
+            };
+
+            ClassWithProperty<T> wrappedValue = new()
+            {
+                Property = value
+            };
+
+            string json = JsonSerializer.Serialize(value, options);
+            Assert.Equal(expectedValueAsString, json);
+
+            T deserializedValue = JsonSerializer.Deserialize<T>(json, options);
+            Assert.Equal(value, deserializedValue);
+
+            json = JsonSerializer.Serialize(wrappedValue, options);
+            Assert.Equal($"{{\"Property\":{expectedValueAsString}}}", json);
+            ClassWithProperty<T> deserializedWrappedValue = JsonSerializer.Deserialize<ClassWithProperty<T>>(json, options);
+            Assert.Equal(wrappedValue.Property, deserializedWrappedValue.Property);
+        }
+
+        public static IEnumerable<object[]> GetTestData()
+        {
+            NumberFormatInfo nfi = CultureInfo.InvariantCulture.NumberFormat;
+
+            yield return GetTestCase("0", Int128.Zero);
+            yield return GetTestCase("-1", new Int128(ulong.MaxValue, ulong.MaxValue));
+            yield return GetTestCase(Int128.MaxValue.ToString(nfi), Int128.MaxValue);
+            yield return GetTestCase(ulong.MaxValue.ToString(nfi), new Int128(0UL, ulong.MaxValue));
+            yield return GetTestCase(ulong.MaxValue.ToString(nfi) + "173", new Int128(0UL, ulong.MaxValue) * 1000 + 173);
+
+            yield return GetTestCase("0", UInt128.Zero);
+            yield return GetTestCase(UInt128.MaxValue.ToString(nfi), UInt128.MaxValue);
+            yield return GetTestCase(ulong.MaxValue.ToString(nfi), new UInt128(0UL, ulong.MaxValue));
+            yield return GetTestCase(ulong.MaxValue.ToString(nfi) + "173", new UInt128(0UL, ulong.MaxValue) * 1000 + 173);
+
+            yield return GetTestCase("0", Half.Zero);
+            yield return GetTestCase(Half.MaxValue.ToString(nfi), Half.MaxValue);
+            yield return GetTestCase(Half.MinValue.ToString(nfi), Half.MinValue);
+            yield return GetTestCase(((Half)1.45f).ToString(nfi), (Half)1.45f);
+
+            yield return GetTestCase("0", BigInteger.Zero);
+            yield return GetTestCase("1", BigInteger.One);
+            yield return GetTestCase(ulong.MaxValue.ToString(nfi), (BigInteger)ulong.MaxValue);
+            yield return GetTestCase("-123", (BigInteger)(-123));
+
+            static object[] GetTestCase(string expectedValue, object value) => new object[] { expectedValue, value };
+        }
+
+        internal class ClassWithProperty<T>
+        {
+            public T Property { get; set; }
+        }
+
+        internal class HalfConverter : SimpleConverter<Half>
+        {
+            public override Half Parse(string value) => Half.Parse(value, CultureInfo.InvariantCulture.NumberFormat);
+            public override string ToString(Half value) => value.ToString(CultureInfo.InvariantCulture.NumberFormat);
+        }
+
+        internal class UInt128Converter : SimpleConverter<UInt128>
+        {
+            public override UInt128 Parse(string value) => UInt128.Parse(value, CultureInfo.InvariantCulture.NumberFormat);
+            public override string ToString(UInt128 value) => value.ToString(CultureInfo.InvariantCulture.NumberFormat);
+        }
+
+        internal class Int128Converter : SimpleConverter<Int128>
+        {
+            public override Int128 Parse(string value) => Int128.Parse(value, CultureInfo.InvariantCulture.NumberFormat);
+            public override string ToString(Int128 value) => value.ToString(CultureInfo.InvariantCulture.NumberFormat);
+        }
+
+        internal class BigIntegerConverter : SimpleConverter<BigInteger>
+        {
+            public override BigInteger Parse(string value) => BigInteger.Parse(value, CultureInfo.InvariantCulture.NumberFormat);
+            public override string ToString(BigInteger value) => value.ToString(CultureInfo.InvariantCulture.NumberFormat);
+        }
+
+        internal abstract class SimpleConverter<T> : JsonConverter<T>
+        {
+            public abstract T Parse(string value);
+            public abstract string ToString(T value);
+
+            public override T Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+            {
+                if (reader.HasValueSequence)
+                {
+                    return Parse(Encoding.UTF8.GetString(reader.ValueSequence));
+                }
+                else
+                {
+                    return Parse(Encoding.UTF8.GetString(reader.ValueSpan));
+                }
+            }
+
+            public override void Write(Utf8JsonWriter writer, T value, JsonSerializerOptions options)
+            {
+                writer.WriteRawValue(ToString(value));
+            }
+        }
+    }
+}
diff --git a/src/libraries/System.Text.Json/tests/System.Text.Json.Tests/System.Text.Json.Tests.csproj b/src/libraries/System.Text.Json/tests/System.Text.Json.Tests/System.Text.Json.Tests.csproj
index 4efc9ade0fd0e4..749f6364889bac 100644
--- a/src/libraries/System.Text.Json/tests/System.Text.Json.Tests/System.Text.Json.Tests.csproj
+++ b/src/libraries/System.Text.Json/tests/System.Text.Json.Tests/System.Text.Json.Tests.csproj
@@ -226,6 +226,9 @@
     <Compile Include="Utf8JsonWriterTests.cs" />
     <Compile Include="Utf8JsonWriterTests.WriteRaw.cs" />
   </ItemGroup>
+  <ItemGroup Condition="$([MSBuild]::IsTargetFrameworkCompatible('$(TargetFramework)', 'net7.0'))">
+    <Compile Include="Serialization\ConvertersForUnsupportedTypesFunctionalTests.cs" />
+  </ItemGroup>
   <ItemGroup>
     <Compile Include="..\..\src\System\Text\Json\BitStack.cs" Link="BitStack.cs" />
   </ItemGroup>