Four Seasons Hotel Miami

Single-swim admission is not available to members of the general public, unless registered as guests at the hotel.

Registered guests only: Free.

There is a semi-circular inset for a whirlpool bath in the center of one end of the pool and one side of the pool has staircase entries along its length, but there is a section on the other side of the whirlpool that's about 14f or 15f wide that looks like it would be perfect for a couple of people to knock off some laps.

There is also a 25y pool at the hotel, but it is too shallow for swimming - "The shallow water level invites the placement of lounge chairs in the pool…"