Credit card, preferably single foreign currency single unionpay. I can't remember what card Costa needs to bind. If you don't like credit cards, bring cash. You must want dollars on the boat.

Sun protection, it is easy to get sunburned at sea.

Swimsuit, come to the cruise, it is wrong not to get into the water.

Know the information of the restaurant in advance, make an appointment in advance, plan ahead, eat what you should, and avoid getting off the boat with regrets.

If you have a trip ashore, bring UnionPay. Shore shopping stores will basically support UnionPay. After all, you have to earn money from China people.

Take a wifi overseas. If you go ashore, you can finally get online. If you surf the internet on the boat, local tyrants can consider it.

Bring some local currency, although it is basically unnecessary, but it is always necessary to buy water, snacks and have a meal on the shore, and you can't find an army.