The Irazú is an active stratovolcano located in the ‘Cordillera Central Volcánica’, in Costa Rica. It peaks at 3,432 meters. It is located inside the national park of the same name about thirty kilometers from San Rafael de Oreamuno, in the province of Cartago. It is sometimes called the twin volcano of Turrialba because they rest on the same base. The crater hosts an acid lake. The intra-crater area consists of three main structures: the active part with a diameter of 1 km and a depth of 180 m that hosts a colorful lake; Diego de la Haya Fernández crater (inactive) is located north of the volcanic crater with a depth of 80 m and to the side a large semi-planar structure that corresponds to the remains of an old terrace called Playa Hermosa and we also find remains of an edge of an ancient volcanic crater. Northeast of the main crater are lava flows and south of the main peak is found the pyroclastic cone of Mount Noche Buena, Mount Pasqui and Mount Guardián. The last eruption took place en1963 but frequent earthquakes indicate that magma is still moving under the volcano. There is also a fumarole field that maintains assets northwest in the outer wall of the main crater.
You can climb to the top of the volcano by car or bus; it will take you 1 hour to 1 hour 30 minutes from San José. The only problem is that the cloud layer begins to get thick around 10:00, so you must arrive early; the park opens at 8:00. By the way, there is only one bus that leaves San Jose at 8:00 am arriving at the summit at 9h30-10h00 and departs around 12:30. At the top, the temperature drops a lot and usually there is a strong wind, thick fog and a small cold rain then it is better to bring warm clothes and waterproof if possible. There is no accommodation or camping in the park, just a small reception center where you can have a coffee to warm you after the visit and toilets. The best season to visit is the dry season, between January and April. If possible do not go on weekends or public holidays to be able to visit out of the crowd. Because of the altitude, you may feel that you lack a little oxygen, stay calm because this is normal.