diff --git a/.changelog/unreleased/improvements/2949-reduce-protoio-writer-creation-time.md b/.changelog/unreleased/improvements/2949-reduce-protoio-writer-creation-time.md
new file mode 100644
index 00000000000..75838e24882
--- /dev/null
+++ b/.changelog/unreleased/improvements/2949-reduce-protoio-writer-creation-time.md
@@ -0,0 +1,2 @@
+- `[p2p/channel]` Speedup `ProtoIO` writer creation time, and thereby speedup channel writing by 5%.
+  ([\#2949](https://github.com/cometbft/cometbft/pull/2949))
\ No newline at end of file
diff --git a/libs/protoio/writer.go b/libs/protoio/writer.go
index 0eb65850cfd..d1f6f03d1bc 100644
--- a/libs/protoio/writer.go
+++ b/libs/protoio/writer.go
@@ -42,7 +42,7 @@ import (
 // equivalent to the gogoproto NewDelimitedWriter, except WriteMsg() also returns the
 // number of bytes written, which is necessary in the p2p package.
 func NewDelimitedWriter(w io.Writer) WriteCloser {
-	return &varintWriter{w, make([]byte, binary.MaxVarintLen64), nil}
+	return &varintWriter{w, nil, nil}
 }
 
 type varintWriter struct {
@@ -69,6 +69,9 @@ func (w *varintWriter) WriteMsg(msg proto.Message) (int, error) {
 	}
 
 	// fallback
+	if w.lenBuf == nil {
+		w.lenBuf = make([]byte, binary.MaxVarintLen64)
+	}
 	data, err := proto.Marshal(msg)
 	if err != nil {
 		return 0, err