Some of the country's finest climbing and trekking is found about 60km (37mi) south of Quito in Parque Nacional Cotopaxi, whose cone-shaped centerpiece, 5900m (19,350ft) Volcán Cotopaxi, is the world's tallest active volcano. Don't attempt to climb higher than the José Ribas refuge (at 4800m/15,750ft) without a guide, proper equipment and a good deal of previous snow and ice climbing experience. Further south, the town of Baños makes a good base for short walks and ambitious climbs, and it has the added bonus of having toasty thermal springs nearby.
Near Cuenca in the southern highlands, the Area Nacional de Recreación Las Cajas offers rugged hiking in bleak terrain scattered with beautiful lakes. Ecuador's highest peak, the 6310m (20,700ft) Chimborazo, is not for daytrippers - if you're not an experienced climber, stick to the area around the mountain, which is great for less strenuous treks.
Ecuador has warm coastal water year round. There are decent swimming beaches at Atacames, San Vicente, Bahía de Caráquez, Bahía de Manta, Salinas and Playas. Beware of the strong undertow at Atacames, which claims victims every year.
Scuba diving is possible in the Galápagos Islands, but you must have your own equipment and book a tour in advance. Snorkeling in the archipelago is less of a hassle - you may even find baby sea lions approaching to stare at you through your mask. Again, bring your own gear and book ahead.
Jungle excursions in the Oriente can be arranged at Misahualí, Coca, Baños, Dureno, Tena and Quito. Excursions often include walks, swims and dugout-canoe trips. Birdwatching is best on jungle tours or while visiting Area Nacional de Recreación Las Cajas, Parque Nacional Cotopaxi or the Galápagos Islands.