Operation Sea Lion

European history

Written by

The Information Architects of Encyclopaedia Britannica

Last updated

July 13, 2026

Quick Summary

Operation Sea Lion was the planned but ultimately postponed German invasion of Great Britain during World War II. Following the fall of France in 1940, Germany's military, the Luftwaffe, needed to achieve air superiority over the English Channel to enable an amphibious assault. However, the Royal Air Force (RAF) successfully defended Britain in the Battle of Britain. This air victory prevented the necessary conditions for invasion, leading to Operation Sea Lion being indefinitely postponed in October 1940. Germany then shifted its focus to invading the Soviet Union.12

Summary created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

2 Britannica Sources

Ask Britannica AI about this topic

Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.

20th-century international relations
The Western front
…plans on July 2 for Operation Sea Lion, the cross-Channel invasion. Such an operation required complete air superiority, and Göring promised that the Luftwaffe could smash British air defenses in four days. The Battle of Britain that followed in August 1940 was a massive air duel between Germany’s 1,200 bombers…
Read More
…plans on July 2 for Operation Sea Lion, the cross-Channel invasion. Such an operation required complete air superiority, and Göring promised that the Luftwaffe could smash British air defenses in four days. The Battle of Britain that followed in August 1940 was a massive air duel between Germany’s 1,200 bombers…
Read More

Third Reich
Early conquests and the expanding war
…lacking, and in October 1940 Operation Sea Lion, the invasion of Britain, was postponed indefinitely.
Read More
…lacking, and in October 1940 Operation Sea Lion, the invasion of Britain, was postponed indefinitely.
Read More