If you want to swim for exercise, the Taipei Daan Sports Center is a good place to do so.
We went there with a friend who lives close to the Gongguan station, so we met up with her there and walked with her for 20 minutes from there. To get there we took the Songshan-Xindian Line, to Xindian for 13 minutes, to the station Gongguan, and then exit from exit 2. Then we walked straight west for about 20 minutes until we reached the sports center. Otherwise, we would have to take two different buses that would take 44 minutes in total, first one from Taipei Circle (Nanjing), either number 288 or 306 or Nanjing Metro Bus, to Nanjing & Jianguo Intersection, then walk three minutes to Zhongshan Girls High School and take the R57 to Daan Sports Center.
When we walked in to the building, we first had to have our temperature checked and write our name, phone number and the time we arrived, as well if we had been out of Taiwan in the last 14 days. Then we went to the pay desk that is opposite to the entrance and said that we wanted to swim, paid NTD $110 for it and got a card together with the receipt. The swimming pool is to the right side of the pay desk, it has a sign over the chairs that you walk down. There you use the card you got, you slip it into the gate and then walk in. Then walk left for the ladies’ and right for the men’s. The changing room has lockers which cost NTD $10 for a small one and NTD $20 for a bigger. The key has a strap so you can wear it on your wrist or ankle. The showers are private with curtains, you should shower both before and after. There are both western and traditional toilets.
We didn’t know this, but apparently you need to wear a swim cap in the pool. We didn’t have any so they gave us one to use. The pool water is warm, but not deep at all. You can always stand in the water, so you can’t use pool for diving. They also have saunas, which are next to the pools.
We couldn't take any pictures inside because that isn't allowed so we just took some from google this time.