diff --git a/lib/bucket_store/gcs.rb b/lib/bucket_store/gcs.rb
index e4b97fe..88c387b 100644
--- a/lib/bucket_store/gcs.rb
+++ b/lib/bucket_store/gcs.rb
@@ -3,17 +3,21 @@
 require "stringio"
 require "uri"
 
-require "google/cloud/storage"
-
 module BucketStore
   class Gcs
     DEFAULT_TIMEOUT_SECONDS = 30
 
+    def self.load_client_library
+      @load_client_library ||= require "google/cloud/storage"
+    end
+
     def self.build(timeout_seconds = DEFAULT_TIMEOUT_SECONDS)
-      Gcs.new(timeout_seconds)
+      new(timeout_seconds)
     end
 
     def initialize(timeout_seconds)
+      self.class.load_client_library
+
       # Ruby's GCS library does not natively support setting up a simulator, but it allows
       # for a specific endpoint to be passed down which has the same effect. The simulator
       # needs to be special cased as in that case we want to bypass authentication,
diff --git a/lib/bucket_store/s3.rb b/lib/bucket_store/s3.rb
index 89b5ef3..5be5919 100644
--- a/lib/bucket_store/s3.rb
+++ b/lib/bucket_store/s3.rb
@@ -2,18 +2,22 @@
 
 require "uri"
 
-require "aws-sdk-s3"
-
 module BucketStore
   class S3
     DEFAULT_TIMEOUT_SECONDS = 30
 
+    def self.load_client_library
+      @load_client_library ||= require "aws-sdk-s3"
+    end
+
     def self.build(open_timeout_seconds = DEFAULT_TIMEOUT_SECONDS,
                    read_timeout_seconds = DEFAULT_TIMEOUT_SECONDS)
-      S3.new(open_timeout_seconds, read_timeout_seconds)
+      new(open_timeout_seconds, read_timeout_seconds)
     end
 
     def initialize(open_timeout_seconds, read_timeout_seconds)
+      self.class.load_client_library
+
       @storage = Aws::S3::Client.new(
         http_open_timeout: open_timeout_seconds,
         http_read_timeout: read_timeout_seconds,
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 6ae9b4d..9470f69 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -1,5 +1,6 @@
 # frozen_string_literal: true
 
+require "logger"
 require "bucket_store"
 
 RSpec.configure do |config|