US to Japan Plug Adapter, Japan Power Travel Adpter with 4 Outlets 4 USB Ports(2 USB C), Type A Plug Adapter for Amercian USA to Japanese China Canada Mexico Philippines Peru Travel Essentials

I use this one that is an EU plug which leaves the NA plug(s) open for hair dryer and cpap: European Travel Plug Adapter,... https://www.amazon.com/dp/B0DLB1FJ72?ref=ppx_pop_mob_ap_share I have used it on Allure and Celebrity ships with no issue.