Cell phones in Puna have always been a little bit of an issue. Anywhere in Hawaii, even on Oahu there are still areas where there is no or very bad connection. I also wanted to add that the coverage shown on the coverage maps is a general prediction of outdoor coverage, and does not guarantee that coverage will be available at all covered geographic areas at all times.
Wireless coverage is impacted by, among other things, terrain, weather, antenna location, system modification, foliage and man-made structures (such as buildings), and therefore cannot be predicted precisely at all times. But I still think that you will get a general idea about cell phones in Puna.
Verizon Wireless: very spotty, probably ok between Keaau and Mountainview, Volcano and Pahoa area (incl. Nanawale and possibly Leilani Estates). Looks like there is no coverage for large parts of HPP, Orchidland, Ainaloa. No coverage from Kapoho to Kalapana.
T-mobile: T-mobile has broad coverage in Puna with best reception in Keaau, Mountainview, Volcano and Pahoa. Areas from Keaau up to Volcano and from Keaau to Pahoa are largely covered. Leilani Estates is possible. Everything past Leilani on the Kapoho side and the Kalapana side has no coverage.
Cingular Wireless / ATT Wireless: Cingular Wireless has had probably the best reception in Puna for many years. You will be able to get a good signal in most of the areas of Puna. The only big exception is the area around Kalapana including Balck Sand Beaches Subdivision and Kalapana Seaview Estates. But Pohoiki towards Leilani Estates and Kapoho, Nanawale Estates, Hawaiian Beaches, Hawaiian Parks, Hawaiian Paradise Park, Pahoa, Ainaloa, Tiki Gardens and basically all the subdivisions from Keaau to Volcano Village.
Sprint Nextel: Sprint Nextel has just expanded its network in Hawaii and added 10 new cell sites on the Big Island. That means also better reception for the Pahoa/Puna area. Additionaly, Sprint customers can now experience the Sprint Mobile Broadband Network, which uses EV-DO (Evolution Data Optimised) Revision (Rev), throughout the Hawaii. Sprint also enhanced coverage for customers state-wide by upgrading many existing cell sites to carry both iDEN and CDMA technology.