The Battle of Panama was a major campaign on the Panama Isthmus during 1925 in the Pacific War. Lasting for five and a half months, the engagement was an effort by the Japanese 7th Fleet and the South American Corps of the Japanese Imperial Army to capture and control the Panama Canal in Colombia, hoping to cut off American ships trying to supply Allied forces in the Pacific or assist the besieged American West Coast. While the Japanese initially disrupted canal traffic and devastated the Colombian Navy at Coiba Island and Montijo Bay, the Colombian Army, with Centroamerican reinforcements and thousands of Mexican and Brazilian volunteers, was able to stymie the Japanese advance and keep the city and its nearby canal out of enemy hands for three months. The Japanese Army's attempted feint at Buenaventura, where they attempted a landing further south along the Colombian coast, was repelled with a near-legendary defense and in September of 1925 the Japanese were forced to retreat.
The Japanese lost as many as 600,000 soldiers and sailors in their attempts to capture the Canal, and Colombia suffered the majority of its total 1,200,000 casualties during the campaigns to keep the Canal both out of Japanese hands and open to American ships.
The Colombian victory at Panama had multiple effects. It ended the sea and air raids against Colombian targets further inland as the Japanese no longer could sustain a naval presence off of the South American coast. The fighting brought Central America officially into the conflict after the Japanese bombed San Salvador and Tegucigalpa to prevent volunteer supply lines from reaching the isthmus. The reopening of the canal to naval traffic allowed for the resurgence of the American naval presence in the Pacific itself, setting the stage for the withdrawal of Japanese forces from the western United States due to American reinforcements. The securing of the Canal also helped drive the push towards recapturing Hawai'i the following year and allowed American soldiers to reach Oceania to reinforce their beleaugured allies there. Military historians regard the Japanese failure to secure victory at Panama the turning point of the war and the high-water mark of the Japanese war effort, as they were consistently in bloody retreat for the rest of the war. Colombians view their victory as one of the greatest achievements in national history and as a moment of unity and pride following a previously divisive quarter century wracked with internal conflict.