Tokyo International Airport (Haneda Airport) is located at Ota-ku, Tokyo. Since international flights have been increasing from this airport, it may be suitable to call it as a gateway of Japan instead of call it as the gateway of Tokyo. It will be convenient to use a rental car, since the airport is a little bit far from central Tokyo and many tourist sites.
Togoshi-koen was built using the heirloom mansion of Kumamoto-Domain Hosokawa clan and it is a part of Chisen-Kaiyushiki garden which is a Japanese style garden with a path around a central pond and spring. You can enjoy seasonal flowers.
Port of Tokyo Wild Bird Park (Tokyo Koyacho Park) is located along the shore with the size of about 250,000 square meters. Annually, 120 kinds of wild birds have been observed and there are plenty of facilities in the park such as the Observation Square with equipped telescopes, the observation shed where you can see wild birds up close.
You can enjoy the sports facilities and open spaces at the Heiwanomori Park. There are 45 kinds of field athletics including archery and tennis courts in the park.