The Cíes Islands, 35 km (21 miles) west of Vigo, are among Spain's best-kept secrets. They form a pristine nature reserve that's one of the last unspoiled refuges on the Spanish coast. Starting on weekends in May and then daily from June–late September, Naviera Mar de Ons (986/225272, www.mardeons.com) runs about eight boats from Vigo's harbor (subject to weather conditions), returning later in the day, for the round-trip fare of €18.50 (tickets must be booked in advance on the website). The 45-minute ride brings you to white-sand beaches surrounded by turquoise waters brimming with marine life; there's also great birding. The only way to get around is your own two feet: it takes about an hour to cross the main island. If you want to stay overnight, there's a designated camping area.
Estación Marítima, Vigo, 36202, Spain