Following commissioning, "Saury" conducted tests in the New London, Connecticut, area and as far south as Annapolis, Maryland, before visiting New York City in late April for the 1939 New York World's Fair. In mid-May, she conducted tests with experimental periscopes, then prepared for her shakedown cruise which, between 26 June and 26 August, took her from Newfoundland to Venezuela and the Panama Canal Zone and back to southern New England. In September, she entered the Portsmouth Navy Yard in Kittery, Maine, for post-shakedown overhaul.