diff --git a/stdlib/buffer.ml b/stdlib/buffer.ml
index 3f02df61c..39f1cc0d2 100644
--- a/stdlib/buffer.ml
+++ b/stdlib/buffer.ml
@@ -279,7 +279,7 @@ let to_seq b =
   let rec aux i () =
     if i >= b.position then Seq.Nil
     else
-      let x = Bytes.get b.buffer i in
+      let x = Bytes.unsafe_get b.buffer i in
       Seq.Cons (x, aux (i+1))
   in
   aux 0
@@ -288,7 +288,7 @@ let to_seqi b =
   let rec aux i () =
     if i >= b.position then Seq.Nil
     else
-      let x = Bytes.get b.buffer i in
+      let x = Bytes.unsafe_get b.buffer i in
       Seq.Cons ((i,x), aux (i+1))
   in
   aux 0