Meeting People in London
London might seem a daunting and scary place full of strangers at first, but in my experience it's very easy to meet people here. Loads of people in their 20's flock to London on working holiday visas from Canada, South Africa, New Zealand and Australia, so there will be lots of people in the same boat as you who will be looking for mates.
Live at a Hostel
If you arrive and don't know a single soul as I did, your best bet for meeting like minded people will be to stay in a backpacker's hostel for awhile. While it'll be more expensive than finding a bed in a house, it's a great way to meet lots of people quickly. Many hostels have people staying long term, so chances are good that a core group will be formed for you to hang out with and you might meet people to lease a house with or even one person to be a roommate.
I would 100% recommend staying at the Barmy Badger Backpacker's in Earl's Court on arrival if you think staying awhile in a hostel is up your alley. I stayed there my first five months in London and another friend of mine stayed about six months and we both had fantastic experiences and met some great people.
Move into a Sociable Sharehouse
Moving straight into a house will save you money in the long run, but you run the risk of isolation if you find that you don't get along with your new housemates. Before you move in, try to gauge whether or not your potential new housemates are friendly and sociable. Moving into a place where everyone hides in their rooms or does their own thing isn't really going to help you meet new people. Larger sharehouses tend to be party places and are good for meeting lots of people.
Join a Sports Team
Once you're settled in a house or hostel you might find that you only really hang out with people you live with. If you want to branch out a bit and make some friends outside your living quarters then I'd say join a sports team. There are loads of leagues around for pretty much every sport you can imagine. I played netball over the winter and met lots of Aussies and Kiwis in the process and played softball in the summer and met mostly North Americans and English people. Most leagues will give you a choice between competitive teams and social, so if you're in it for a bit of exercise and a lot of drinking and fun, social leagues are fantastic.
Go on an Organised Tour
Another great way to meet lots of people is by taking a tour. I'm not a big fan of organised tours but it can't be denied that they're popular with people who are on their way to live in London. Many people choose to do a bit of travelling before they arrive and move to London right aftertaking a tour around Europe. Most people I've met who have taken Contiki Tours talk about how much fun they were, but more than that, how many people they met and stayed in touch with once they got settled in London.
If all else fails, you can always count on the trusty ol' internet. There are lots of networks for expats in London including groups for Canadians and Americans abroad, social networks based on the area you live, groups based around hobbies etc. The Gumtree community section is a good place to start. If you're looking to find romance check out Speed Dater, Slow Dating or Single Solution.
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