During the 19th century, the volcano erupted and emitted ash several times (1847, 1853, 1855, 1859, 1866), producing pyroclastic flows.
The last major eruption was in 1866.

Small signs of activity start in 1996.

In January 2001, the volcano reported increased activity, displaying strong fumarole activity at the central craters.
The volcanic activities have increased since 2005.

On March 31, 2017, the volcano started to show some activity with ash eruptions.

The National Park area opened for visitors was closed from 2009 to 2011.

On January 8, 2010, a phreatic eruption occurred, creating a new opening near the crater on the southwest, and the temperature increased from 200 to 600 °C (392 to 1,112 °F).
Two villages, La Central and El Retiro, were evacuated.

On January, 2012 a new opening on the west of the crater was created after a phreatic eruption.

On April 12, 2012, a small eruption occurred.

On May 21, 2013, at 08:52, a gas explosion widened several openings near the main crater that appeared in 2010 and 2012.

In July 2013 researchers found that tremors around the area increased from about twenty earthquakes a day, to up to thirty per hour.

On October 17, 2014, the quantity of tremors increased from around 50-100 a day, to 200 a day.

On October 29, 2014, at around 10:10, a tremor started and kept constant, until a phreatic eruption occurred around 23:10 at the west opening that appeared in January 2012.
This eruption sent a large amount of volcanic material to areas up to 40 km (25 mi) away.
Many citizens reported ash falling on their properties and a strong odor of sulphur in the cantons of Vásquez de Coronado, Goicoechea, Moravia, Desamparados, Aserrí, Escazú, Santa Ana, Montes de Oca, Tibás, Alajuelita, Puriscal, San José in the province of San José, La Union in the province of Cartago and Santo Domingo and Heredia, in the province of Heredia.
During the 19th century, the volcano erupted and emitted ash several times (1847, 1853, 1855, 1859, 1866), producing pyroclastic flows. The last major eruption was in 1866.
Small signs of activity start in 1996.
In January 2001, the volcano reported increased activity, displaying strong fumarole activity at the central craters. The volcanic activities have increased since 2005.
On March 31, 2017, the volcano started to show some activity with ash eruptions.
The National Park area opened for visitors was closed from 2009 to 2011.
On January 8, 2010, a phreatic eruption occurred, creating a new opening near the crater on the southwest, and the temperature increased from 200 to 600 °C (392 to 1,112 °F). Two villages, La Central and El Retiro, were evacuated.
On January, 2012 a new opening on the west of the crater was created after a phreatic eruption.
On April 12, 2012, a small eruption occurred.
On May 21, 2013, at 08:52, a gas explosion widened several openings near the main crater that appeared in 2010 and 2012.
In July 2013 researchers found that tremors around the area increased from about twenty earthquakes a day, to up to thirty per hour.
On October 17, 2014, the quantity of tremors increased from around 50-100 a day, to 200 a day.
On October 29, 2014, at around 10:10, a tremor started and kept constant, until a phreatic eruption occurred around 23:10 at the west opening that appeared in January 2012. This eruption sent a large amount of volcanic material to areas up to 40 km (25 mi) away. Many citizens reported ash falling on their properties and a strong odor of sulphur in the cantons of Vásquez de Coronado, Goicoechea, Moravia, Desamparados, Aserrí, Escazú, Santa Ana, Montes de Oca, Tibás, Alajuelita, Puriscal, San José in the province of San José, La Union in the province of Cartago and Santo Domingo and Heredia, in the province of Heredia.
Turrialba Volcano