Tunisia has a well-developed transport network, with just about every town of any consequence linked daily with the capital. Things get crowded during August and September and around holidays, so book ahead if possible.
Tunisia's domestic air network is fairly limited - there just aren't that many places far enough from Tunis to warrant catching a plane. Four airports catch domestic flights from Tunis - Gafsa, Jerba, Sfax and Tozeur - and no flight takes more than an hour.
The national bus company, Société Nationale du Transport Interurbain (SNTRI, pronounced 'sintry'), operates daily air-conditioned buses to just about every town in the country. Their services are fast, comfy and affordable. In summer, they run at night to avoid the midday heat; book ahead at this time. In addition, there are regional bus companies that are cheap, but slower than SNTRI, and almost never air-conditioned.
The train network run by the Société Nationale des Chemins de Fer Tunisiens (SNCFT) is well short of comprehensive, but it is modern and efficient and they do run on time. The main line runs several times a day between Tunis and Gabès via Sousse and Sfax. One train branches off at Mahrès to Gafsa and Metlaoui. Other destinations include Bizerte, Mateur, Ghardimao, Jendouba, Kalaat Khasba, Bir Bou Rekba, Nabeul, Monastir and Mahdia. For train enthusiasts, the Lezard Rouge (Red Lizard) is a restored beylical train that runs between Metlaoui and Redeyef daily, offering magnificent views of the Seldja Gorge.
Tunisia's shared, long-distance taxis - called louages - take five passengers and won't leave until they're full (which never takes long). Louages are the fastest way to get around and the cost is only slightly higher than that for a bus. To find one, look for a white Peugeot station wagon with roof racks and identification signs on the front and back. There's always someone shouting out destinations and directing people to specific louages near their 'depots' - usually a vacant lot in the town centre. The government sets the rates, so if you think you're being ripped off, ask to see the list of tariffs before getting in.
Driving around Tunisia is a treat - at least in the north. The roads are excellent and drivers are generally safe and courteous. The only things to watch out for are weaving moped drivers (of which there are bountiful numbers) and errant pedestrians. Fuel is cheap by European standards, but lead-free petrol is not widely available and car rental costs are exorbitant. Driving is on the right.
There are two regular ferry services in the country. One connects Sfax with the Kerkennah Islands, about 25km (15mi) off the coast. The second runs from Jorf on the mainland to Ajim on the island of Jerba. Fares are very cheap.
Bicycles are available for hire around the country. Conditions are ideal, save for summer heat, winter cold and the dearth of quality spare parts - fill out your repair kit before you leave home.
Tunis also has a modern métro léger (tram) network, which is much easier to use than the buses, as well as a suburban train line (TGM) that connects the city centre with the northern suburbs.