The main town, Lenakel, is on the island's western side. A road goes north to the airport and south around the island. Another road passes through the middle of it (Middle Bush) to "the other side" where Mt Yasur is.
Air Vanuatu has one to two flights a day to Whitegrass airport on Tanna from Port Vila. The flights are quite expensive at 140 USD one way. Connections to Santo are also possible. This is the most expensive way to get to Tanna.
Belair does a loop of the airports on the islands to the south, including Tanna, from Port Vila at least twice a week. Confirm flights.
At least two cargo boats go between Tanna and Port Vila, around once a week. Schedules are unpredictable, although departures are usually early in the morning. Call Touaraken at 5656689 or 7719809 and Sarafenua at 24135 to check when the next boat might leave. The price is 5000-5500 vatu one way. The passage takes 12-16 hours but beware as the seas in the area are particularly rough and could lead to severe seasickness in unprepared voyagers. There are also no designated sleeping spaces and you would likely have to spend the voyage sitting in the covered compartment on the deck.
Tanna is quite touristy and locals are used to tourists chartering transport. If you are staying at a resort, arrange your transport there. For independent travelers: trucks are used by local people to travel around the island. These go at irregular times and a good place to wait is the small "roundabout" one block inland from the harbour. Ask around where the trucks go from. Monday, Wednesday and Friday are market days and therefore busier. A ride between Lenakel and the area around Mt Yasur should cost 500 vatu per person. A chartered vehicle will set you back 5-10,000 vatu.
Minibuses run regularly between Lenakel and the airport for 300 vt.
The area around Mt Yasur is good to explore on foot.
Mount Yasur is an active volcano, 361 m (1,184 ft) above sea level, often called "the most accessible active volcano on earth". The glow of the volcano was apparently what attracted Captain James Cook to the island in 1774. The volcano can be climbed up to the rim and provides some stunning photo opportunities. Because of the variability of the eruptions, the local government has created safety levels: Level 0 - Low activity, access to the crater allowed; Level 1 - Normal activity, access to the crater allowed; Level 2 - Moderate to high activity, lava bombs may land beyond the crater rim, access to the crater is closed; Level 3 - Severe activity, access to the summit zone is closed; Level 4 - Major eruption, all access closed.
Beware that a few people have been killed by lava bombs in the past. A Tour Guide must be used. The entry fee very high at 9750 vatu per adult and 7150 vatu per kid under 12, less for your second visit (keep the ticket if you are planning to visit again).
There is a road that goes almost to the crater rim. Most people go to see the volcano at sunset, after dark the volcano puts on a fantastic show. People who stay at resorts around Lenakel usually see the volcano on an organized tour. Otherwise it is much better to stay in the many bungalows, campsites and treehouses that are close to the volcano. It would then be perfectly possible to walk up to the rim and ask for a ride back on one of the tourist trucks. Otherwise a chartered truck for seeing the volcano from the villages around it should not cost more than 9750 vatu per adult and 7150 vatu per kid under 12. Bring a torch.
In the area of Mt Yasur there are other places to see. Port Resolution and Sulphur bay are both walking distance and have hot springs and beaches. The ash plane around the volcano is worth exploring too, including the small canyon through which the lake that was on the plane drained to the sea in the year 2000 after heavy rain. On Friday nights the John frum movement has a ceremony which can be visited. Once a year(Feb 15th) they have a parade with flags and marching.
Oppisite of the vulcano entrance there is a cannibal tour which gives you an experience like arriving as the first foreigner on the island. They will explain hunting, planting and eating customs of the original Tanna people and costs 1500vt pp.
Buy laplap at the market on Monday, Wednesday or Friday. There are also a few restaurants in Lenakel that will sell simple meals of rice and meat/chicken for 3-400 vatu. There is a small cafe in Port Resolution (Chez Leah) that sells simple souvenirs and local meals. However, the owner may not always be available. Otherwise while travelling through villages feel free to ask the locals whether anyone could prepare a simple meal for you.
Kava, of course. On Tanna traditionally kava is prepared by virgin boys chewing it and then spitting it out into a bowl before the kava is mixed with water. You will find this in villages at traditional nakamals. Be careful, however, as diseases or parasites may spread through direct contact, water, or saliva. The kava at the kava bar in Lenakel is prepared in the "normal" way - by grinding. The famous Tanna Coffee is harvested on the island, however the processing takes place in Port Vila and the end product is cheaper there.
There are a few cheap guesthouses in Lenakel. One is behind the bank/Air vanuatu office and charges 1500 vatu per person. Ask the other, better guesthouses too and ask for a second price (no bargaining in Vanuatu!).
Virtually any village in the Mt Yasur area will have some kind of bungalow, campsite or better type of accommodation.
Bring a jacket. It gets cold, especially around the volcano.
The same way as you got in, or take a flight or ask for a boat that goes to the other islands in Tafea. All domestic flights require a VUV200 to be paid after checking in, typically at a dedicated booth near the airline counters.