diff --git a/src/Servers/Kestrel/Core/test/AsciiDecoding.cs b/src/Servers/Kestrel/Core/test/AsciiDecoding.cs
index 32faf184c5e1..bd39c9c93620 100644
--- a/src/Servers/Kestrel/Core/test/AsciiDecoding.cs
+++ b/src/Servers/Kestrel/Core/test/AsciiDecoding.cs
@@ -5,6 +5,7 @@
 using System.Linq;
 using System.Numerics;
 using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Infrastructure;
+using Microsoft.AspNetCore.Testing;
 using Xunit;
 
 namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests
@@ -110,6 +111,7 @@ private void DifferentLengthsAreNotEqual()
         }
 
         [Fact]
+        [QuarantinedTest("https://github.com/dotnet/aspnetcore/issues/31500")]
         private void AsciiBytesEqualAsciiStrings()
         {
             var byteRange = Enumerable.Range(1, 127).Select(x => (byte)x);
diff --git a/src/Servers/Kestrel/test/InMemory.FunctionalTests/Http3/Http3StreamTests.cs b/src/Servers/Kestrel/test/InMemory.FunctionalTests/Http3/Http3StreamTests.cs
index 9884b40cf504..cc72ccb0e96c 100644
--- a/src/Servers/Kestrel/test/InMemory.FunctionalTests/Http3/Http3StreamTests.cs
+++ b/src/Servers/Kestrel/test/InMemory.FunctionalTests/Http3/Http3StreamTests.cs
@@ -1623,6 +1623,7 @@ await requestStream.WaitForStreamErrorAsync(
         }
 
         [Fact]
+        [QuarantinedTest("https://github.com/dotnet/aspnetcore/issues/31501")]
         public async Task DataBeforeHeaders_UnexpectedFrameError()
         {
             var requestStream = await InitializeConnectionAndStreamsAsync(_noopApplication);