1. Online second-hand market: such as idle fish, transfer, melon seeds used car and other platforms. Many people on these platforms sell second-hand swimming equipment. You can choose the right equipment by screening, comparing and contacting the seller.

2. Second-hand shops: Some cities will have some second-hand shops or flea markets. You can go to these places to see if there are any suitable swimming equipment for sale.

3. Swimming clubs or gyms: Some swimming clubs or gyms may upgrade their equipment or replace old equipment. You can ask the administrators or coaches in these places if there are any unused second-hand swimming equipment for sale.