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Operation Sealion is Germany's code name for the planned invasion of Britain in 1940. It could have happened after a victory of the Luftwaffe in the Battle of Britain. Find out in this game how in could have unfolded.
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Tracked since Jul 7, 2026.
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Operation Sea Lion, also written as Operation Sealion (from German: Unternehmen Seelöwe), was Nazi Germany's code name for their planned invasion of the United Kingdom. It was to have taken place during the Battle of Britain, thirteen months after the start of the Second World War. Following the Battle of France and that country's capitulation, Adolf Hitler hoped the British government would accept his offer to end the state of war. He considered invasion to be a last resort, to be used only if all other options had failed. And it seemed to be the case, especially with an opponent like Winston Churchill.
As a precondition for the invasion of Britain, both air and naval superiority over the English Channel and the proposed landing sites was mandatory. Other conditions; such as suitable landing crafts and forces, and naval transportation for resupply, were also required.
SGS Sealion explores the possible German invasion based on the assumption that all necessary requirements were met during the summer and a window of opportunity opens in September 1940.
While it is to be assumed that the British had already lost the eponymous Battle of Britain, the RAF is not completely out of the fight just yet, and the Royal Navy still presents a credible threat to the Germans’ amphibious landings and supply conduits across the English Channel.
On the ground, the Germans have operational superiority, but the British Army can rely on their interior lines of communication and defensible terrain, including a crude network of hastily constructed fortifications that had been built before the invasion.
Scenario durations last from 2 turns (for the smaller ones) to over 30 turns, each representing one-day period between early September 1940 and the beginning of October. One player leads Axis land, air and naval forces, while the other commands those of Great Britain and its various allies present in England at the time (Poles, Canadians, Free French, etc…).
The British have very few good quality land troops (mostly Guard and some rare elite divisions, even if depleted), but their navy is still basically intact and could take, even with overwhelming losses, the chance to kill the invasion in a brilliant naval dash. And the RAF, although severely battered, is not totally absent either. Good defenses, and internal lines may favor also some good reactivity.
The German (and later Italian allies help) have veteran ground forces, and the Luftwaffe reign in the skies, although sometimes limited in operational range and presence. The navy is lacking on all points, but has gathered enough strength and means to support a one-time, hopefully decisive, effort.
Capturing key choke points, supply heads and decisive locations will tell whether the invasion is a success or a failure. Time is passing fast, and poor weather arriving in October may tell the end of the show, either in victory or defeat, for both sides. It’s a race against time and elements, with barely enough resources.
The game’s event cards allow full replay ability thanks to the numerous various situations that they create on the diplomatic, military, political or economical fields.
Estimated Playtime: from 1-10h
Favored Side: none.
Hardest to Play: German.
