With a 30 minute flight from Chofu City airfield or a 45 minute flight from Haneda Airport, you can reach Tokyo's closest major outlying island: Izu Oshima (伊豆大島). Izu Oshima is actually considered part of Tokyo. The island was designated a national park for its unique geological features. The park is well known as a place to view gigantic surface strata.
The island has over 3 million blooming camellia trees. Their petals can be used to dye fabrics. You can try for yourself during any season at the Dream Studio (夢工房). Silk is best for the first time. The owner is very kind and patient with students. The owner also speaks English, so the experience is also popular with English speakers from overseas.
In addition, diving and trekking are popular activities on the island. As far as diving, Wanko Marine (和光マリン) is recommended. Staff able to communicate in English are always stationed, so it is convenient for non-Japanese speakers. For trekkers, hiking up to Mt. Mihara is your best option. Even for those not confident in their hiking skills, it is a comparatively easy hike which will offer a view of the volcano and its surroundings. Also, on the opposite side of the mountain is Urasabaku. The view alone is worth coming to the island, some visitors remark. At dusk, you can see beams of light from the sky as if it is being absorbed by the earth. The first time you see Urasabaku, your heart races as your eyes soak in a treasure you will never forget.
Upon visiting Izu Oshima, it will forever occupy a part of your heart. If you are looking for a short adventure, by all means head to Izu Oshima Island. Kind and friendly people will welcome you with open arms.