Currently erupting:

Ambrym (Vanuatu): active lava lakes in several craters (updated 12 Jul 2016)
Batu Tara (Sunda Islands, Indonesia): strombolian explosions, ash plumes up to 500 m, extrusion of a small lava dome with rockfalls (updated 28 Nov 2015)
Bristol Island (United Kingdom, South Sandwich Is): new eruption since late April 2016 (updated 21 Jul 2016)
Bromo (East Java, Indonesia): intermittent mild ash emissions (updated 2 Aug 2016)
Chikurachki (Paramushir Island): explosive activity since 27 July 2016 (updated 28 Jul 2016)
Colima (Western Mexico): intermittent mild to moderate explosions (updated 29 Jul 2016)
Copahue (Chile/Argentina): strombolian activity from new intra-crater cone (updated 4 Jul 2016)
Dukono (Halmahera): mild strombolian activity, continuous intense ash emissions (updated 12 Jul 2016)
Erebus (Antarctica): active lava lake in summit crater (updated 8 Dec 2014)
Erta Ale (Danakil depression, Ethiopia): overflowing lava lake (updated 2 Mar 2016)
Fuego (Guatemala): lava flows on S and W flanks, lava fountaining from summit vent (updated 30 Jul 2016)
Gamalama (Halmahera): small ash eruption on 3 Aug 2016 (updated 3 Aug 2016)
Ibu (Halmahera, Indonesia): stromolian and phreatomagmatic explosions (updated 29 Oct 2015)
Kilauea (Hawai'i): new surface lava flows from breakouts N and NE of Puu Oo since 24 May 2016 (updated 28 Apr 2015)
Klyuchevskoy (Kamchatka): strombolian explosions in summit crater, active lava flows on SE flank (updated 25 Jul 2016)
Masaya (Nicaragua): active lava lake ini summit crater (updated 12 Jul 2016)
Nevado del Ruiz (Colombia): intermittent mild to moderate ash emissions (updated 29 Jul 2016)
Nevados de Chillán (Central Chile): sporadic ash emissions (updated 2 Aug 2016)
Nyiragongo (DRCongo): new vent on crater floor (updated 1 Jun 2016)
Ol Doinyo Lengai (Tanzania): effusion of natrocarbonatite lava inside the crater (updated 8 Jul 2013)
Pacaya (Guatemala): strombolian explosions (updated 29 Jul 2016)
Pavlof (Alaska Peninsula, USA): currently calm (updated 29 Jul 2016)
Popocatépetl (Central Mexico): degassing, sporadic explosions, slowly growing lava dome (updated 25 Jul 2016)
Reventador (Ecuador): lava flow on SW flank (updated 24 Feb 2016)
Sakurajima (Kyushu, Japan): sporadic vulcanian explosions from Minamidake and Showa crater (updated 25 Jul 2016)
Sangay (Ecuador): mild strombolian activity in summit crater (updated 20 May 2016)
Santiaguito (Guatemala): intermittent strong explosions from growing Caliente dome (updated 16 Jul 2016)
Semeru (East Java, Indonesia): growing lava dome, mild strombolian activity in summit crater (updated 29 Jul 2016)
Shiveluch (Kamchatka): growing lava dome (updated 29 Jul 2016)
Sinabung (Sumatra, Indonesia): continuing pyroclastic flows (updated 1 Aug 2016)
Stromboli (Eolian Islands, Italy): weak, intermittent strombolian explosions (updated 23 May 2016)
Turrialba (Costa Rica): near-continuous ash emissions (updated 25 Jul 2016)
Villarrica (Central Chile): lava lake in summit crater, spattering, strombolian explosions (updated 4 Apr 2016)
Yasur (Tanna Island, Vanuatu): ash emissions, weak strombolian explosions (updated 13 Nov 2015)

Eruption warning / minor activity:

Alaid (Northern Kuriles): strombolian activity and lava flows in summit crater (updated 21 Jul 2016)
Aso (central Kyushu, Japan): degassing, sporadic steam / ash explosions (updated 8 Mar 2016)
Awu (North Sulawesi & Sangihe Islands): seismic unrest, eruption warning (updated 13 May 2016)
Bagana (Bougainville Island, Papua New Guinea): intermittent mild ash emissions (updated 29 Jul 2016)
Barren Island (Indian Ocean): weak thermal hot spot (updated 3 Mar 2016)
Bezymianny (Central Kamchatka Depression): steaming (updated 30 Jul 2016)
Brava (Cape Verde)
Bulusan (Luzon Island, Philippines): degassing (updated 29 Jul 2016)
Canlaon (Central Philippines): degassing, sporadic ash emissions (updated 29 Jul 2016)
Cerro Negro (Nicaragua): increased earthquake activity (updated 16 Feb 2016)
Chirpoi (Kurile Islands, Russia): degassing, steaming (updated 29 Jul 2016)
Etna (Sicily, Italy): occasional ash puffs from New SE crater, increased degassing (updated 19 Apr 2014)
Heard (Australia, Southern Indian Ocean): strombolian activity, lava flow from Mawson Peak summit crater (updated 1 Feb 2016)
Karangetang (Siau Island, Sangihe Islands, Indonesia): rockfalls, glowing lava dome (updated 13 Jan 2016)
Karymsky (Kamchatka): weak activity (rare explosions?) (updated 16 Jun 2016)
Langila (New Britain, Papua New Guinea): ash emissions (updated 13 May 2016)
Lokon-Empung (North Sulawesi, Indonesia): seismic unrest, eruption warning (updated 9 Mar 2016)
Manam (Papua New Guinea): occasional ash emissions, thermal anomaly at crater (updated 13 Jul 2016)
Merapi (Central Java, Indonesia): sporadic phreatic explosions (updated 21 Aug 2015)
Michael (United Kingdom, South Sandwich Is): possible intermittent ash emissions (updated 3 Jun 2016)
Momotombo (Nicaragua): intermittent vulcanian explosions (updated 29 Mar 2016)
Niigata-Yake-yama (Honshu): sporadic explosions, seismic unrest (updated 8 May 2016)
Nyamuragira (DRCongo): small active lava lake in summit caldera (as of end of April 2016) (updated 12 Jun 2016)
Piton de la Fournaise (La Réunion): seismic unrest, inflation (updated 29 Jul 2016)
Poas (Costa Rica): sporadic phreatic explosions (updated 29 Jul 2016)
Rincón de la Vieja (Costa Rica): sproadic hydrothermal explosions (updated 3 May 2016)
Rinjani (Lombok): sudden eruption on 1 Aug 2016 (updated 2 Aug 2016)
Sabancaya (Peru): steaming, elevated seismic activity (updated 12 Jul 2016)
San Miguel (El Salvador): seismic unrest, inflation, strong degassing (updated 19 Jun 2016)
Sangeang Api (Indonesia): weak lava extrusion from summit crater (updated 11 Nov 2015)
Suwanose-jima (Ryukyu Islands): steaming, occasional ash emissions from On-take crater (updated 25 Jul 2016)
Telica (Nicaragua): lava glow from crater, degassing, occasional light ash emissions (updated 9 May 2016)
Tungurahua (Ecuador): inflation, eruption warning (updated 5 Jun 2016)
Ubinas (Peru): sporadic vulcanian explosions (updated 16 Jan 2016)
Zavodovski (South Sandwich Islands (UK)): strong steaming, degassing (updated 18 Jun 2016)