Portugal has a public transport network that allows you to reach many beaches without a car. It's not always the most comfortable option, and some remote beaches are genuinely difficult to reach without a vehicle, but for most main beaches there is a reasonable solution.
Lisbon: beaches within 1 hour
- Costa da Caparica — Fertagus train to Pragal + bus, or ferry from Cais do Sodré + bus
- Cascais/Estoril — direct CP train line from Lisboa-Cais do Sodré, every 20 minutes
Porto: beaches within 30 minutes by metro
Porto Metro has a direct line to Matosinhos beach (line A — Blue). For beaches further north like Espinho, there are frequent CP train departures.