Seafood bought from Hainan can be checked in, but it must comply with the airline’s regulations on fresh items. Under normal circumstances, seafood needs to be kept fresh, so appropriate preservation measures need to be taken, such as using ice bags, ice cubes, etc., and informing the airline when checking in to ensure that the seafood can reach its destination safely. However, it is recommended to consult the airline or relevant shipping agency for specific information on whether it can be checked and how to operate it.