Ultimately, it depends on what you want from your holiday. Buses and trains run regularly along the length of the Algarve so, if you're just planning on travelling to the beach and back to your hotel every day, you're well catered for. If you want to explore the area, you might need to hire a car, though, as a lot of the prettiest villages and beaches have no access to public transport. It's also hard to get a bus after eight in the evening and getting one on weekends and public holidays is a bit hit and miss, too.