Suncheon's official Onnuri public-bike system currently reports 68 unmanned rental stations and app-based QR rental and return. The official instructions say users must be at least 15 and complete identity verification during membership signup.
That verification step matters for foreign visitors. The official page does not clearly document which overseas phone numbers, foreign-resident credentials or passport-only users are accepted, so do not assume you can register after arriving at a rack. Install the app and attempt signup before you depend on the bike for a timed connection.
The official service page lists rental availability from 00:00 to 24:00, a basic rental period of 180 minutes and an additional charge of 500 won per 30 minutes beyond the basic period. It also notes that bikes must be rented and returned at designated unmanned stations. Check the current app for the actual plan/payment terms that apply to your account.
For a visitor, the bike works best as an optional local mobility layer, not as the only way back to a train or bus. Check live station availability before walking to a rack and keep a city-bus or taxi fallback for the return.