diff --git a/hpb/hpb.h b/hpb/hpb.h
index 319d944dfe..96737c9060 100644
--- a/hpb/hpb.h
+++ b/hpb/hpb.h
@@ -152,7 +152,7 @@ constexpr uint32_t ExtensionNumber(
 }
 
 template <typename T>
-typename T::Proxy CreateMessage(::hpb::Arena& arena) {
+typename T::Proxy CreateMessage(hpb::Arena& arena) {
   return typename T::Proxy(upb_Message_New(T::minitable(), arena.ptr()),
                            arena.ptr());
 }
@@ -279,7 +279,7 @@ absl::StatusOr<T> Parse(absl::string_view bytes,
 }
 
 template <typename T>
-absl::StatusOr<absl::string_view> Serialize(const T* message, upb::Arena& arena,
+absl::StatusOr<absl::string_view> Serialize(const T* message, hpb::Arena& arena,
                                             int options = 0) {
   return ::hpb::internal::Serialize(hpb::interop::upb::GetMessage(message),
                                     ::hpb::interop::upb::GetMiniTable(message),
@@ -287,7 +287,7 @@ absl::StatusOr<absl::string_view> Serialize(const T* message, upb::Arena& arena,
 }
 
 template <typename T>
-absl::StatusOr<absl::string_view> Serialize(Ptr<T> message, upb::Arena& arena,
+absl::StatusOr<absl::string_view> Serialize(Ptr<T> message, hpb::Arena& arena,
                                             int options = 0) {
   return ::hpb::internal::Serialize(hpb::interop::upb::GetMessage(message),
                                     ::hpb::interop::upb::GetMiniTable(message),