Types of Transport
There are public busses in Efate and Espiritu Santo (east coast), but not in Tanna. There are no fixed bus routes though - a public bus is a minibus, and the driver is the owner of the bus.
If you flag down an empty bus, you will set the destination, and along the way, the driver will pick up people that are going in the same direction. If the bus is full, ask the driver if they are heading in that direction. If not, they'll simply tell you so, otherwise, you can hop in.
A bus far is usually 150 vatu to 200 vatu, and up to 500 for longer distancces. Watch how much the locals pay the driver and pay the same as they do. If you ask the driver how much, they may tell you that the fee is up to 500 vatu - which is reasonable for a longer trip but not for an inner city commute. If they tell you anymore, there's no need to get angry - just smile, laugh, say "that's not the fee, the fee is 150". There's no need to be rude, and who can blame a bus driver for playing the hustle with a foreigner.
A taxi from the Bauerfield International Airport on Efate to Port Vila cost a flat fee of 1,400 vatu. If there are multiple planes landing around the same time though, drivers may request a higher fare. If you're travelling on a tighter budget, you can walk 20 minutes to the Kumul Highway / Rte to Mele roundabout (GPS location: -17.706037, 168.308811). From here, you can catch a local bus into Port Vila for 150 vatu. Any bus heading south will be going to Vila, although many of them may be passing through the residential areas - which could take up to an hour. If you're not in a rush, you may find it interesting to see what life looks like for the inhabitants of Port Vila, and you may make some friends on the bus. Locals will usually laugh and say hello when they see a foreigner taking their transport.
Hitchhiking is very easy in Vanuatu, although the only limitation is that not many cars go past! When hitchhiking in any direction, I recommend you keep walking, as you may get to your destination quicker by walking than via car. Make sure to bring a hat and sunscreen, and enjoy the fresh air!
In Efate, you'll need to take a public bus out of the city in order to get a hitchhiking ride around the island. Once you get past Manga'asi, cars will become less frequent and you may only have one go past per hour. It is polite to give the driver 150 vatu for picking you up. Foreigners and other travellers are slightly more likely to pick you up than locals, as locals are often driving only small distances.
In Espiritu Santo, fewer people own a car in Efate, but hitchhiking is still very common. Here you'll likely be picked up in utes where you sit in the back of the tray. Again, it is polite to give the driver 150 vatu for the ride, and in Espiritu Santo drivers are more likely to ask you to pay. If you ask them how much the fee is, they will generally tell you a higher fee, so I recommend just watch the other locals and pay as they do - in 2024 this was 150 vatu.
In Tanna, very few people own a car. It is hard to hitchhike as not many cars go past. We were able to hitchhike from near the airport to Tanna quite successfully on the back of a few construction trucks, as long as you don't mind sitting on a pile of bricks and holding on to the metal grate as you go over deeply rutted roads. Our ride dropped us off on the Ash Plains and from there, we were able to walk to our accommodation. We hitchhiked a bit more to and from different sites around the volcano, but often we arrived where we wanted to go by foot before any cars passed. I wouldn't recommend hitchhiking to the airport on the day of your departing flight though, as it may take a few hours to get all the way via hitchhiking. Either hitchhike the day before and stay near the airport overnight, or ask your accommodation to organise an airport transfer for you (2,500 vatu per person).