A medical social security card can buy several tickets for Gulangyu Island in Xiamen.

If you are a social security card in Xiamen and the social security is still in the state of insurance payment, you can take a boat to Gulangyu Island at Xiamen Ferry Terminal, and you can enjoy the preferential price for Xiamen citizens to buy tickets without going to Du Dong Cruise Center.

According to Xiamen Ferry Co., Ltd. "Regulations on the Administration of Public Transport Boat Routes":

Article 2 Passengers must abide by the following provisions on ticket management:

(1) Xiamen Citizen Dedicated Line (Xiamen Ferry Pier to Gulangyu Piano Pier and Shantou Pier to Neicuo 'ao Pier) is only for Xiamen registered population or people with valid Xiamen social security cards. Passengers must purchase citizen discount tickets (referred to as "boat tickets") with valid Xiamen identity cards or valid Xiamen social security cards, and each card is limited to one boat ticket. The ID card or social security card used at the time of ticket purchase will be used as the ticket checking certificate, and the ticket is a real-name registration system ticket.

Further reading: How to buy insurance, which is good, and teach you how to avoid these "pits" of insurance.