State-run telecommunications company Etecsa has a monopoly as Cuba's internet service provider. For public internet access, almost every provincial town has an Etecsa telepuntos center where you can wait in line to enter and buy a one-hour user card (CUC$1.50) with scratch-off usuario (code) and contraseña (password) to use at computers onsite or in a public wi-fi area (usually the central plaza of a town). Cards can be used for multiple internet sessions.
There are few, if any, independent internet cafes outside the telepuntos. As a general rule, most three- to five-star hotels (and all resort hotels) have wi-fi and internet terminals. They also can be a more convenient place to buy scratchcards, though some hotels charge abusive rates for them (sometimes as much as CUC$7 per hour).
Very few casas particulares offer internet, but their numbers are growing.
Warning: connections are often slow and temperamental, particularly at peak times (late afternoon and early evening).