Before we proceed, this guide is written under the presumption that you will be playing as either Germany or Italy (the two major European Axis nations). If you’re playing as the German Reich, it may be worth your time to read my nation guide on them before you proceed, as it will provide useful tips on certain points such as: how to spend your political points; general military tactics; what to prioritise in terms of industry; and much more. A nation guide for Italy will be coming soon.
Moving on, it is vital that you have a strong air force and navy by the time you come to war in 1939. In terms of your air force you should put particular focus on fighters (for air superiority) and naval bombers (to help crush the British and French navy). With this, it is good practice to have a least four thousand planes by 1939 with a mix of fighters, close air support and naval bombers. In regard to your navy, this will be different dependent on whether you play as the German Reich or Italy. See below:
As Germany it is unlikely you’re going to match the surface capabilities of the British and French navy – unless you go down the ‘Oppose Hitler’ path which would see naval reconstruction come as one of the national focuses. You should place a great deal of attention on submarines and convoys. By the time you go to war, you should have at least one hundred and fifty submarines and by having a high number of convoys this will help ensure the invasion actually takes place. To maximise the capabilities of your naval forces you should go down the ‘Trade Interdiction’ naval doctrine as these will help the convoy raiding stats on your submarines and make them more effective against the British. Please note, you should not place your navy in the English Channel or North Sea before your naval bombers have dealt a sufficient blow to the Allied vessels. If you’re worried about Britain or Free France launching a naval invasion, it may be worth setting up a garrison across the ports you own (you could use cheap division templates to ensure equipment and manpower was not wasted).
When it comes to the invasion itself, be sure to have both naval and air superiority to make sure the invasion itself is a successful. It is worth having two invasion plans: one can be in South of England such as Portsmouth and the other in the South West like Kent. Moreover, have about five divisions in each invasion force with two armies of twenty-four being ready to back them up once the beach has landed. You must spread out your troops quick as the AI will quickly reinforce but be careful not to have encircled divisions as your invasion will likely fail. Once you have both armies in Britain, be swift, ruthless and take no prisoners and then the sun should finally set over the British Empire.
Italy (Roman Empire)
I've included Italy in this guide, as I know many players enjoy attempting to reform the Roman Empire and some of the territories required to complete this include Britain. In terms of the naval invasion itself, the tactics are the same. But, as Italy you should focus more so on surface ships like battleships and carriers. Therefore, you should go down the 'Fleet in Being' naval doctrine as this best suits Italy. In addition, be sure to dedicate troops to the African theatre to capture the Suez Canal, which will cut the Allies off from the Far East.
I appreciate that this guide only talks about the situation of two nations within the game. Despite this, the tactics are similar for any nation you play as. As long as you have the three key items: a good place to launch the invasion; a strong air force; and capable navy then you should be fine. Move quickly when you’ve invaded and be sure to have troops ready to reinforce the beach head.
If the tips provided in the guide did or did not work for you, then please let me know in the comments section below. Furthermore, if you’re interested in more HOI4 guides then you check out my nation guides on the Soviet Union, German Reich and France.