diff --git a/src/iceberg/catalog/memory/in_memory_catalog.cc b/src/iceberg/catalog/memory/in_memory_catalog.cc
index d644c44fe..9e4a485a0 100644
--- a/src/iceberg/catalog/memory/in_memory_catalog.cc
+++ b/src/iceberg/catalog/memory/in_memory_catalog.cc
@@ -21,7 +21,6 @@
 
 #include <algorithm>
 #include <iterator>
-#include <mutex>
 
 #include "iceberg/table.h"
 #include "iceberg/table_metadata.h"
@@ -337,42 +336,42 @@ std::string_view InMemoryCatalog::name() const { return catalog_name_; }
 
 Status InMemoryCatalog::CreateNamespace(
     const Namespace& ns, const std::unordered_map<std::string, std::string>& properties) {
-  std::lock_guard guard(mutex_);
+  std::unique_lock lock(mutex_);
   return root_namespace_->CreateNamespace(ns, properties);
 }
 
 Result<std::unordered_map<std::string, std::string>>
 InMemoryCatalog::GetNamespaceProperties(const Namespace& ns) const {
-  std::lock_guard guard(mutex_);
+  std::shared_lock lock(mutex_);
   return root_namespace_->GetProperties(ns);
 }
 
 Result<std::vector<Namespace>> InMemoryCatalog::ListNamespaces(
     const Namespace& ns) const {
-  std::lock_guard guard(mutex_);
+  std::shared_lock lock(mutex_);
   return root_namespace_->ListNamespaces(ns);
 }
 
 Status InMemoryCatalog::DropNamespace(const Namespace& ns) {
-  std::lock_guard guard(mutex_);
+  std::unique_lock lock(mutex_);
   return root_namespace_->DropNamespace(ns);
 }
 
 Result<bool> InMemoryCatalog::NamespaceExists(const Namespace& ns) const {
-  std::lock_guard guard(mutex_);
+  std::shared_lock lock(mutex_);
   return root_namespace_->NamespaceExists(ns);
 }
 
 Status InMemoryCatalog::UpdateNamespaceProperties(
     const Namespace& ns, const std::unordered_map<std::string, std::string>& updates,
     const std::unordered_set<std::string>& removals) {
-  std::lock_guard guard(mutex_);
+  std::unique_lock lock(mutex_);
   return root_namespace_->UpdateNamespaceProperties(ns, updates, removals);
 }
 
 Result<std::vector<TableIdentifier>> InMemoryCatalog::ListTables(
     const Namespace& ns) const {
-  std::lock_guard guard(mutex_);
+  std::shared_lock lock(mutex_);
   const auto& table_names = root_namespace_->ListTables(ns);
   ICEBERG_RETURN_UNEXPECTED(table_names);
   std::vector<TableIdentifier> table_idents;
@@ -387,6 +386,7 @@ Result<std::unique_ptr<Table>> InMemoryCatalog::CreateTable(
     const TableIdentifier& identifier, const Schema& schema, const PartitionSpec& spec,
     const std::string& location,
     const std::unordered_map<std::string, std::string>& properties) {
+  std::unique_lock lock(mutex_);
   return NotImplemented("create table");
 }
 
@@ -394,6 +394,7 @@ Result<std::unique_ptr<Table>> InMemoryCatalog::UpdateTable(
     const TableIdentifier& identifier,
     const std::vector<std::unique_ptr<TableRequirement>>& requirements,
     const std::vector<std::unique_ptr<TableUpdate>>& updates) {
+  std::unique_lock lock(mutex_);
   return NotImplemented("update table");
 }
 
@@ -401,22 +402,24 @@ Result<std::shared_ptr<Transaction>> InMemoryCatalog::StageCreateTable(
     const TableIdentifier& identifier, const Schema& schema, const PartitionSpec& spec,
     const std::string& location,
     const std::unordered_map<std::string, std::string>& properties) {
+  std::unique_lock lock(mutex_);
   return NotImplemented("stage create table");
 }
 
 Result<bool> InMemoryCatalog::TableExists(const TableIdentifier& identifier) const {
-  std::lock_guard guard(mutex_);
+  std::shared_lock lock(mutex_);
   return root_namespace_->TableExists(identifier);
 }
 
 Status InMemoryCatalog::DropTable(const TableIdentifier& identifier, bool purge) {
-  std::lock_guard guard(mutex_);
+  std::unique_lock lock(mutex_);
   // TODO(Guotao): Delete all metadata files if purge is true.
   return root_namespace_->UnregisterTable(identifier);
 }
 
 Status InMemoryCatalog::RenameTable(const TableIdentifier& from,
                                     const TableIdentifier& to) {
+  std::unique_lock lock(mutex_);
   return NotImplemented("rename table");
 }
 
@@ -426,31 +429,40 @@ Result<std::unique_ptr<Table>> InMemoryCatalog::LoadTable(
     return InvalidArgument("file_io is not set for catalog {}", catalog_name_);
   }
 
-  Result<std::string> metadata_location;
+  std::string metadata_location;
   {
-    std::lock_guard guard(mutex_);
+    std::shared_lock lock(mutex_);
     ICEBERG_ASSIGN_OR_RAISE(metadata_location,
                             root_namespace_->GetTableMetadataLocation(identifier));
   }
 
   ICEBERG_ASSIGN_OR_RAISE(auto metadata,
-                          TableMetadataUtil::Read(*file_io_, metadata_location.value()));
+                          TableMetadataUtil::Read(*file_io_, metadata_location));
 
-  return std::make_unique<Table>(identifier, std::move(metadata),
-                                 metadata_location.value(), file_io_,
+  return std::make_unique<Table>(identifier, std::move(metadata), metadata_location,
+                                 file_io_,
                                  std::static_pointer_cast<Catalog>(shared_from_this()));
 }
 
 Result<std::shared_ptr<Table>> InMemoryCatalog::RegisterTable(
     const TableIdentifier& identifier, const std::string& metadata_file_location) {
-  std::lock_guard guard(mutex_);
+  if (!file_io_) [[unlikely]] {
+    return InvalidArgument("file_io is not set for catalog {}", catalog_name_);
+  }
+
+  ICEBERG_ASSIGN_OR_RAISE(auto metadata,
+                          TableMetadataUtil::Read(*file_io_, metadata_file_location));
+
+  std::unique_lock lock(mutex_);
   if (!root_namespace_->NamespaceExists(identifier.ns)) {
     return NoSuchNamespace("table namespace does not exist.");
   }
   if (!root_namespace_->RegisterTable(identifier, metadata_file_location)) {
     return UnknownError("The registry failed.");
   }
-  return LoadTable(identifier);
+  return std::make_unique<Table>(identifier, std::move(metadata), metadata_file_location,
+                                 file_io_,
+                                 std::static_pointer_cast<Catalog>(shared_from_this()));
 }
 
 }  // namespace iceberg
diff --git a/src/iceberg/catalog/memory/in_memory_catalog.h b/src/iceberg/catalog/memory/in_memory_catalog.h
index 5d1f2e13c..e6a9acbce 100644
--- a/src/iceberg/catalog/memory/in_memory_catalog.h
+++ b/src/iceberg/catalog/memory/in_memory_catalog.h
@@ -19,7 +19,7 @@
 
 #pragma once
 
-#include <mutex>
+#include <shared_mutex>
 
 #include "iceberg/catalog.h"
 
@@ -103,7 +103,7 @@ class ICEBERG_EXPORT InMemoryCatalog
   std::shared_ptr<FileIO> file_io_;
   std::string warehouse_location_;
   std::unique_ptr<class InMemoryNamespace> root_namespace_;
-  mutable std::recursive_mutex mutex_;
+  mutable std::shared_mutex mutex_;
 };
 
 }  // namespace iceberg