Paradox Interactive has announced Hearts of Iron IV: Thunder At Our Gates, a new Theater Pack for the popular strategic war game set around the time of World War II. The expansion will be released on June 11, 2026, and focuses on Southeast Asia, Australia, and the South Pacific.
Thunder At Our Gates brings new national focus trees for Australia, Siam, and the Dutch East Indies. Players will be able to develop smaller powers into strong defensive states, counter the imperial ambitions of great powers, or pursue their own path of influence expansion.
Australia will have to deal with the consequences of the Great Depression, political challenges, British alliances, and a limited population during the war. Siam gains the ability to balance between civilian and military authority, industrialization, resistance to foreign powers, or a return to the ambitions of the old Rattanakosin Kingdom. The Dutch East Indies will focus on rich reserves of rubber and oil, relations with the Netherlands, and a possible path towards autonomy or independence.
The pack also introduces two new mechanics. Ship Captains bring division commanders into the naval part of the game, while Army Headquarters will allow sending generals to the field to strengthen nearby units, but with the risk of their capture.
Along with the paid expansion, a free update will arrive with numerous changes, including the Regimental Support system, which brings new ways to add support to divisions.
Hearts of Iron IV: Thunder At Our Gates will be available from June 11, 2026, at a recommended price of €19.99.
