| Ireland | Ireland | Ireland | 1980-01-29 | 1980-04-19 | 1980 | 1 | |
| Izmir | Izmir | Turkey, Izmir | 1903-11- | 2013-05- | 1903–2012 | 2 | |
| Idrettsbygget | Idrettsbygget | Norway, Løkken Verk | 1969-09-17 | -- | 1969 | 2 | |
| Iranshahr | Iranshahr | Iran, Tehran, Artists' Park, Iranshahr St. | 2020-02-16 | 2020-03-16 | 2020 | 1 | |
| International Festival of Monodrama - Die Pumpe | International Festival of Monodrama - Die Pumpe | Germany, Kiel | 2006-11-11 | -- | 2006 | 1 | |
| IBSEN Museum & Teater | IBSEN Museum & Teater | Norway, Oslo, Henrik Ibsens gate 26 | 2022-03-20 | 2022-06-12 | 2022 | 2 | |
| Irving Greenberg Theatre Centre | Irving Greenberg Theatre Centre | Canada, Ottawa, 1233 Wellington Street West | 2009-03-10 | 2009-03-21 | 2009 | 1 | |
| Irkutskij dramatičeskij teatr | Irkutskij dramatičeskij teatr (Irkutsk Drama Theatre) | Russia, Irkutsk | 1946-- | -- | 1946 | 1 | |
| Inderøy kulturhus | Inderøy kulturhus | Norway, Inderøy, Vennalivegen 15 | 2001-06-25 | -- | 2001–2006 | 2 | |
| Ilkley Playhouse | Ilkley Playhouse | England, Ilkley | 2024-09-12 | 2024-09-21 | 2024 | 1 | |
| Izmail | Izmail | Ukraine, Izmail | -- | -- | | | |
| Irving Place Theatre | Irving Place Theatre | United States of America, New York, East 15th Street | 1897-04-12 | 1913-11-12 | 1897–1918 | 9 | |
| Ila fengsel | Ila fengsel | Norway, Eiksmarka, Jøssingveien 33 | 2012-11-28 | -- | 2012 | 2 | |
| Intiman, Malmö Stadsteater | Intiman, Malmö Stadsteater | Sweden, Malmö, Östra Rönneholmsvägen 20 | 1954-10-08 | 2015-04-29 | 1954–2015 | 11 | |
| Illnau-Effretikon ZH | Illnau-Effretikon ZH | Switzerland | 2002-11-16 | -- | 2002 | 1 | |
| IATC/UNATC ( National University of Theatre and Film "I.L. Caragiale") | IATC/UNATC ( National University of Theatre and Film "I.L. Caragiale" ) | Romania, Bucharest, Matei Voievod Street 75-77 | 1907-05-26 | 1907-05-27 | 1907–2015 | 9 | |
| Independent Theatre | Independent Theatre | Australia, North Sydney, 271 Miller Street | 1946-10-10 | -- | 1946–1951 | 2 | |
| International Theatre | International Theatre | United States of America, New York | 1946-11-12 | 1947-02-19 | 1946 | 1 | |
| Intimes Theater | Intimes Theater | Switzerland, Bern | 1909-10-21 | 1909-12-01 | 1909 | 1 | |
| Inner Stage, The, University of Guelph | The Inner Stage, University of Guelph | Canada, Guelph, 50 Stone Road East | 1990-11-25 | 1990-12-01 | 1990 | 1 | |
| Iowa City Community Theatre | Iowa City Community Theatre | United States of America, Iowa City, 4261 Oak Crest Hill Rd SE | 2005-03-04 | 2005-03-20 | 2005 | 1 | |
| Inkonst | Inkonst | Sweden, Malmö, Bergsgatan 29 | 2006-09-29 | 2006-10-01 | 2006 | 1 | |
| Imperial Theatre | Imperial Theatre | Canada, Vancouver | 1908-07-09 | 1908-07-09 | 1908 | 1 | |
| Institute of Contemporary Arts (ICA) | Institute of Contemporary Arts (ICA) | England, London, The Mall | 1995-07-04 | 1995-07-08 | 1995 | 1 | |
| Île-Saint-Louis-Paul Rey, Théâtre de l' | Théâtre de l'Île-Saint-Louis-Paul Rey | France, Paris, 39 quai d'Anjou | 2009-04-21 | 2009-05-24 | 2009 | 1 | |
| Instituto Português do Desporto e da Juventude | Instituto Português do Desporto e da Juventude | Portugal, Lisbon | 2023-06-05 | 2023-06-05 | 2023 | 1 | |
| IGS Garbsen | IGS Garbsen | Germany, Garbsen, Meyenfelder Str. 8, | 2010-10-30 | -- | 2010 | 1 | |
| Ibsenparken | Ibsenparken | Norway, Skien | 2006-05-23 | -- | 2006 | 1 | |
| Idavoll | Idavoll | Norway, Ørsta | 1961-01-26 | -- | 1961–1963 | 2 | |
| Isthmus Playhouse. Madison Civic Center | Isthmus Playhouse. Madison Civic Center | United States of America, Madison, 201 State Street | 1999-10-22 | 1999-11-14 | 1999 | 1 | |
| Irish Theatre, The | The Irish Theatre | Ireland, Dublin | 1917-04-23 | 1918-02-09 | 1917–1918 | 2 | |
| Italy | Italy | Italy, Italy | 1918-01- | 1980-03-24 | 1918–2021 | 19 | |
| Incognito Theatre | Incognito Theatre | England, Friern Barnet, London, Holly Park Road | 2005-02-08 | 2012-12-01 | 2005–2012 | 2 | |
| Indiana Repertory Theatre | Indiana Repertory Theatre | United States of America, Indianapolis, 140 W. Washington Street | 2001-01-09 | 2001-02-03 | 2001 | 1 | |
| Idavollen | Idavollen | Norway, Ørstavik | 1952-02-29 | -- | 1952–1956 | 3 | |
| Idrettshallen på Tråstad skole | Idrettshallen på Tråstad skole | Norway, Kongsvinger | 1971-09-29 | 1971-09-29 | 1971 | 1 | |
| Imperial Theatre | Imperial Theatre | England, Westminster, London, Tothill Street | 1903-01-25 | 1903-01-26 | 1903 | 2 | |
| Industrial space | Industrial Space | United States of America, New York, Chelsea | 1994-08- | 1995-11- | 1994 | 2 | |
| Iran Tamasha Venue | Iran Tamasha Venue | Iran, Tehran, No 3, Semnan St., Nejat Elahi St., Ferdowsi square, Enghelab St | 2018-12-28 | -- | 2018 | 1 | |
| International Festival of Monodrama | International Festival of Monodrama | Ukraine, Kiev | 2006-09-23 | -- | 2006 | 1 | |
| Institut Papa Gueye Fall | Institut Papa Gueye Fall | Senegal, Dakar | 2021-05-19 | -- | 2021 | 1 | |
| Imperial Theatre | Imperial Theatre | United States of America, Saint-Louis | 1904-11-17 | 1904-11-17 | 1904 | 1 | |
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