Backpackers will find Hawaii to be a fantastic destination to explore with excellent opportunities for kayaking, hiking and surfing. However, travelling around the islands is not cheap with budget rooms starting at US$40 per night and only a handful of backpacker style hostels with shared rooms or dormitories. Whilst inter-island flights are reasonable (discounts available for about US$50 one way), there is no alternative - the only inter island ferries connect Maui with Lanai and Molokai. The problem comes in getting around the islands - this is the land of the car and the bus network is limited - and taxis are very expensive. Whilst the main island Oahu has an excellent and inexpensive public bus network, the same cannot be said for the other islands where the bus network is both limited and infrequent.
Waikiki has several budget hostels including a YHA for those looking for atmosphere. The north shore is a popular backpacker destination in the summer months when the surfers are out of town. Haleiwa is a popular choice and there are several nice camp grounds along the north shore beaches.
The Big Island of Hawaii is the most popular backpacker destination in Hawaii with several cheap and lively backpacker hostels around the island. The pick of the bunch is Arnott's lodge in the town of Hilo on the east coast. Arnott's lodge offer the only guided walks to the edge of the lava flow at Volcano National Park as well as excellent day tours to Waipio Valley and the summit of Mauna Kea. There are a few cheap guesthouses around Waipio Valley on the north shore, and a handful of budget rooms available for around US$50 per night around the seaside town of Kailua on the west coast. Manago Hostel in South Kona is another lively hostel and serves as a good base for the excellent snorkelling and kayaking around Hanaunau Bay.
Kaua'i has only a handful of budget accommodations, mostly around the seaside town of Lihue in the south east, with the cheapest rooms on the island at Kalaheo along the south coast. The north shore around the charming tropical town of Hanalei has several excellent beaches where camping is allowed, notably Haena Beach Country Park. Other options if travelling in a small group is to rent one of the budget vacation rentals and split the cost.
Maui has even fewer budget hostels, with one in the inland town of Wailuku and several budget bed and breakfasts for less than US$50 per night around the lush town of Hana on the east coast. Hana has some beautiful tropical scenery and there are two State Parks which offer camping. Budget rooms starting at US$60 a night are plentiful around the beach town of Kihei on the south west coast.