Air travel to Qatar has boomed in the last decade. Most visitors to the country arrive via Hamad International Airport (IATA: DOH) near Doha. The national carrier, Qatar Airways, has established an extensive network of flights to 124 destinations from its Doha hub. Flights to Sydney, scheduled to begin in February 2016, make Doha Airport one of the few airports in the world to offer non-stop flights to every inhabited continent. Other major airlines also fly to the airport, usually connecting Doha with their own hub in the base country.
A taxi ride from the airport has a standard fare of QR 25.
The only overland route to Qatar is via Saudi Arabia. Unless you are a citizen of one of the GCC countries, it is quite difficult to obtain a Saudi visa. Tourism is often closed for long periods at short notice and visas are both confusing and expensive. If you want to travel from the UAE, Bahrain and other Gulf countries to Qatar via Saudi Arabia, you need a Saudi transit visa in advance and documents proving that you will continue your journey. There are plans to build a major bridge to connect Qatar with neighbouring Bahrain, but this project is constantly delayed.
Even if you manage to get a Saudi visa, it is not recommended to travel by car. The roads between Qatar and other major cities/countries are in poor condition. When travelling during the day, watch out for fast moving cars and trucks. Always wear your seat belt and do not drive faster than 80 km/h (50 mph). Driving at night is risky, with poor visibility and semi-suicidal drivers.
You can travel by bus from/via Saudi Arabia to Qatar. There are fixed bus routes within Qatar, but they are mainly used by men only. However, customs formalities can take up to 4 hours, especially at night. You will not be treated as well as if you were flying into Doha. Air tickets are only slightly more expensive than bus tickets.
There are no specific routes for boats, but there are commercial cargo boats coming to Doha from all over the world, as well as small commercial boats from Dubai and Iran.