diff --git a/internal/quic/bench_test.go b/internal/quic/bench_test.go
new file mode 100644
index 000000000..f883b788c
--- /dev/null
+++ b/internal/quic/bench_test.go
@@ -0,0 +1,99 @@
+// Copyright 2023 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build go1.21
+
+package quic
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"math"
+	"testing"
+)
+
+// BenchmarkThroughput is based on the crypto/tls benchmark of the same name.
+func BenchmarkThroughput(b *testing.B) {
+	for size := 1; size <= 64; size <<= 1 {
+		name := fmt.Sprintf("%dMiB", size)
+		b.Run(name, func(b *testing.B) {
+			throughput(b, int64(size<<20))
+		})
+	}
+}
+
+func throughput(b *testing.B, totalBytes int64) {
+	// Same buffer size as crypto/tls's BenchmarkThroughput, for consistency.
+	const bufsize = 32 << 10
+
+	cli, srv := newLocalConnPair(b, &Config{}, &Config{})
+
+	go func() {
+		buf := make([]byte, bufsize)
+		for i := 0; i < b.N; i++ {
+			sconn, err := srv.AcceptStream(context.Background())
+			if err != nil {
+				panic(fmt.Errorf("AcceptStream: %v", err))
+			}
+			if _, err := io.CopyBuffer(sconn, sconn, buf); err != nil {
+				panic(fmt.Errorf("CopyBuffer: %v", err))
+			}
+			sconn.Close()
+		}
+	}()
+
+	b.SetBytes(totalBytes)
+	buf := make([]byte, bufsize)
+	chunks := int(math.Ceil(float64(totalBytes) / float64(len(buf))))
+	for i := 0; i < b.N; i++ {
+		cconn, err := cli.NewStream(context.Background())
+		if err != nil {
+			b.Fatalf("NewStream: %v", err)
+		}
+		closec := make(chan struct{})
+		go func() {
+			defer close(closec)
+			buf := make([]byte, bufsize)
+			if _, err := io.CopyBuffer(io.Discard, cconn, buf); err != nil {
+				panic(fmt.Errorf("Discard: %v", err))
+			}
+		}()
+		for j := 0; j < chunks; j++ {
+			_, err := cconn.Write(buf)
+			if err != nil {
+				b.Fatalf("Write: %v", err)
+			}
+		}
+		cconn.CloseWrite()
+		<-closec
+		cconn.Close()
+	}
+}
+
+func BenchmarkStreamCreation(b *testing.B) {
+	cli, srv := newLocalConnPair(b, &Config{}, &Config{})
+
+	go func() {
+		for i := 0; i < b.N; i++ {
+			sconn, err := srv.AcceptStream(context.Background())
+			if err != nil {
+				panic(fmt.Errorf("AcceptStream: %v", err))
+			}
+			sconn.Close()
+		}
+	}()
+
+	buf := make([]byte, 1)
+	for i := 0; i < b.N; i++ {
+		cconn, err := cli.NewStream(context.Background())
+		if err != nil {
+			b.Fatalf("NewStream: %v", err)
+		}
+		cconn.Write(buf)
+		cconn.Flush()
+		cconn.Read(buf)
+		cconn.Close()
+	}
+}
diff --git a/internal/quic/endpoint_test.go b/internal/quic/endpoint_test.go
index 16c3e0bce..6d103f061 100644
--- a/internal/quic/endpoint_test.go
+++ b/internal/quic/endpoint_test.go
@@ -63,7 +63,7 @@ func TestStreamTransfer(t *testing.T) {
 	}
 }
 
-func newLocalConnPair(t *testing.T, conf1, conf2 *Config) (clientConn, serverConn *Conn) {
+func newLocalConnPair(t testing.TB, conf1, conf2 *Config) (clientConn, serverConn *Conn) {
 	t.Helper()
 	ctx := context.Background()
 	e1 := newLocalEndpoint(t, serverSide, conf1)
@@ -79,7 +79,7 @@ func newLocalConnPair(t *testing.T, conf1, conf2 *Config) (clientConn, serverCon
 	return c2, c1
 }
 
-func newLocalEndpoint(t *testing.T, side connSide, conf *Config) *Endpoint {
+func newLocalEndpoint(t testing.TB, side connSide, conf *Config) *Endpoint {
 	t.Helper()
 	if conf.TLSConfig == nil {
 		newConf := *conf