Day and weekly passes
Travelers train too: chains and many neighborhood centers sell single-day or weekly passes with no joining fee, and municipal facilities charge a reduced per-visit rate.
The day pass
Nearly all chains sell it at reception with access to the floor and classes with room: the price of two coffees for an honest workout. Bring a towel — mandatory in several — and a lock for the locker.
The weekly pass
For week-long stays it clearly beats a monthly contract: ask for the visitor modality before accepting anything. The magic words are 'foreign visitor pass'.
No neighborhood borders
Choose the gym by proximity to your hotel, not brand: in one week no service difference pays for the trip. The nearby municipal pool is summer's alternative.