Fairmont Kea Lani, Maui

Single-swim admission is not available to the general public, unless registered as a guest at the hotel.

Registered guests: Free.

There are two other large pools at the resort, one just for kids. The one described above is shaped like a medicine capsule that's been pinched in the middle, reducing the width there to about 20 feet; it's painted or maybe tiled in a dark blue with white insets that could serve to keep you on track for the full 100-foot length.