How you travel to Europe on your gap year really depends on where you're coming from, your first port of call, and where you plan to go from there. The United Kingdom is an excellent place to kick off from, as it's an essential destination if you're not a native, and incredibly easy to get from there into mainland Europe. Here are some of the best ways to do it.
You can fly from pretty much any airport in the UK, even the small ones, to somewhere in mainland Europe. This is often the fastest way to travel, though if you're going from the UK to France the time added on at the airport either side often means it isn't always your best option.
If you're heading north, south, or further east, a plane is recommended, flying into Madrid, Rome, Stockholm, or Moscow being popular starting points. The excellent transport links in Europe make it easy to get wherever your backpacking itinerary dictates.
The Eurostar is an excellent, affordable way to travel from the south of the UK to destinations in France, Belgium, and the Netherlands. To make it into Paris takes no more than a few hours, and not much longer to reach Lille, Lyon, Brussels, or Amsterdam. Or Disneyland Paris, if you're so inclined. It can prove quicker than flying, and is often significantly less stressful. You also have the option of taking a car through the channel tunnel.
It's incredibly easy to get a ferry from numerous spots in the south of the UK to a variety of locations in France, Spain, and Portugal. It's slower than other transport options, but is definitely the most relaxing, and often very reasonably priced.
There are also ferry options in northern and southern Europe, connecting Scandinavian countries more directly with the rest of Europe, and offering routes between locations like Italy and Croatia.