Ferries across the Rio Tejo are run by Transtejo, from terminals at Belém, Cais do Sodré, and Terreiro do Paço. They offer unique views of Lisbon, and their top decks are a nice way to catch the sun. Prices (loaded onto a €0.50 electronic card) run €1.20–€2.70.
Transtejo. 21/213500115; www.transtejo.pt.