Located about 60 mi/100 km northwest of San Jose, Arenal National Park encompasses a large area in northwest Costa Rica, but the most remarkable feature—one of the most impressive sights in the country, in fact—is Arenal Volcano, which has been active since a surprise eruption in 1968.
One of the most popular places for viewing Arenal is at its base, where a volcano-heated stream flows into a small waterfall and then diverts into a series of mineral baths that are part of Tabacon Hot Springs, a resort complex with eight swimming pools. (It welcomes day visitors as well as overnight guests.) You can lie in the pools at night and watch the glowing lava flow down the mountainside.
Because eruptions and weather are unpredictable, it's best to spend at least one night near the volcano, either in the town of La Fortuna or at one of the lodges in the area to maximize chances of viewing the almost daily eruptions (you can ask to be awakened if an eruption happens at night). La Fortuna has a good selection of accommodations, and a nearby waterfall is a worthwhile excursion for experienced hikers. You also can ride horses up to the lava flow, which is also accessible by hiking trails.
The volcano is still considered a potential danger when approaching areas susceptible to pyroclastic flows, so use a qualified guide for these hikes and horseback rides. Note that the side of the crater where lava flows originate will vary as the crater wall builds up and collapses. Viewing the fiery eruptions in the evening may be possible from one location and not possible from there a year later.
Lake Arenal is just west of the volcano, with fishing, hotels and, at the western end of the lake, windsurfing. In fact, some rate it as a world-class spot for the sport because of the strong and constant winds. The vistas are fantastic; many hotels have both lake and volcano views. Although it's only 20 mi/30 km (as the crow flies) from Arenal Volcano to Monteverde Cloud Forest Reserve, the indirect roads and bus connections take the better part of a day. If you're not driving, it's possible to travel via a more direct route, taking a boat across Lake Arenal. We found a great service by Jeep, motorboat and then taxi that cuts the trip to just 2.5 hours.
