The beach strip itself is walkable — the main entrance, the shacks, and the village centre are all within a few minutes on foot of each other.
For anywhere beyond that, a hired scooter or bicycle is the most useful option. Scooters can be rented from several places in the village and in Margao for around ₹300–400 per day; they're the standard way to reach Benaulim, Varca, and the quieter stretches of coast to the south. Bicycles are fine for the flat coastal roads and can be hired more cheaply.
Auto-rickshaws connect Colva to Margao throughout the day for shopping, train connections, and the bus stand. There are no meters — agree on a fare before you get in. The going rate from Colva to Margao is roughly ₹100–150; drivers will quote more and expect to negotiate.
Taxis are available for longer trips. Arrange them through your guesthouse or at the beach, or call ahead for airport transfers.