Please note that the information on hotel gyms below may be incorrect now.
- Jongno-gu (Gyeongbokgung, Changdeokgung, Bukchon Hanok Village, Insadong, Dongdaemun) （鍾路区（景福宮、昌徳宮、北村韓屋村、仁寺洞、東大門））
* As needed, I tried to put links to photos on other websites as much as possible. I can do that to ones on TripAdvisor and some hotel's official website because they create a unique URL for every photo on them. So far, I don't know how to do it for some hotel search sites such as Hotels.com, Booking.com and Google Maps.
Jongno-gu (Gyeongbokgung, Changdeokgung, Bukchon Hanok Village, Insadong, Dongdaemun) （鍾路区（景福宮、昌徳宮、北村韓屋村、仁寺洞、東大門））
Benikea Premier Hotel Dongdaemun （ベニキアプレミアホテル東大門）
I can see some weight plates in one photo on Google Maps*, but I'm not sure what type of weight training facilities the gym has.
Somerset Palace Seoul （サマセットパレスソウル）
The gym is open 24 hours.
Shilla Stay Guwanghwamun （新羅ステイ光化門）
The gym is open from 6am to 11pm.
Aventree Hotel Jongno （アベンツリーホテルジョンノ）
Orakai Insadong Suites （オラカイ仁寺洞スイーツ）