South Observation Deck: 9:30 a.m. - 17:00
North Observation Deck: 9:30 a.m. - 22:30
One of the best free attractions in Tokyo: a view from the 202 meter high Metropolitan Government Building in Shinjuku. On a clear day you can even see Mt. Fuji!
The nearest subway station is Tocho-mae on the Toei Oedo Subway Line, exit A4, but you can also walk there in about 15 minutes from Shinjuku JR Station.