The Pool at Keio Plaza Hotel Tokyo
Keio Plaza Hotel Tokyo's pool is praised by those who travel for a living. Out of 8 reviews that we tracked, 7 referenced the pool, like Rough Guide, Frommer's and Fodor's.
Keio Plaza Hotel Tokyo 
Rough Guide
Frommer's
Fodor's
Lonely Planet
DK Eyewitness
Oyster
Star Service
Rough Guide "There's also an outdoor pool in summer"
Frommer's "); concierge; executive-level rooms; fitness room; outdoor pool w/wading pool; room service; in-house doctor and dentist"
Fodor's "The Sky Pool (on the seventh floor of the Main Building) is actually two pools, one rectangular for laps and the other circular for lounging; both afford views of Shinjuku's steel-and-concrete skyscrapers"
Lonely Planet "Note that the pool is outdoor and only open during the summer"
DK Eyewitness "Given its location among the skyscrapers of West Shinjuku and first-rate amenities, including heated pools, stores, and restaurants, room rates are reasonable"
Oyster " It also has a rooftop pool, full spa and salon, and more restaurants and bars than some small towns"
Star Service "The pool and wading pool for children—both free for hotel guests—sparkle on the seventh-floor terrace linking the two towers, although they are only open in the warmer summer months"
