Moving to Vancouver in a couple of weeks and needing a SIM card to go in my iphone 5.

I know that some networks in Canada are not nationwide - we will be spending time in other cities so my wife's mobilicity plan that only works in about 5% of Canada would not do for me.

I will need a lot or unlimited data - not keen on a long contract, wanting to pay monthly.

Any ideas? what is this thing in the wiki about only 2 networks having GSM??

All the major carriers will be fine in Vancouver, Bell, Telus, Rogers and their subsidiaries Koodoo, Virgin & Fido. Rogers & Fido have slightly worse coverage through the interior.
As long as your phone is unlocked any SIM will work. Also, bringing your own device means you'd be on a month to month contract, so no fixed term. However I've yet to see any provider that offers unlimited data (except Sasktel, which is obvs no use in BC!)

Get one from a convenience store

Try 7Eleven 'Speakout'. Pay as you go.

https://www.speakout7eleven.ca

I had to chop the standard SIM cards down to fit our (wife and I) iPhones, but they may have moved on now and supply Micro SIMs.
We kept the numbers when we later moved onto Bell contracts.

I should have said, I'm in vancouver for a year so PAYG will not do. I expect I'll be chugging data, too

Use free wifi Timmies or Mac Deez

We use Virgin month by month. seems reasonable.

Best deal by far is a corporate plan but you probably can't get on that. If you're looking for nationwide coverage and a lot of data, its gonna be expensive. I'd recommend wind ($40/month unlimited talk/text/data) but they are not nationwide. They are more like mobilicity which you said wouldn't work so i'll cross that off.

You're left with Koodo which will give you

$54/month ($60/month with 10% BYOD discount) + tax.
Unlimited Canada wide talk
Unlimited Text (includes text sent from Canada to international destinations - great for texting mates and family back in UK)
1GB data (not much)

$63/month ($70/month w/10% discount) + tax will get you the same as above but 2GB data instead of 1

$84.60/month ($94/month w/10% discount) + tax will get you same as above but 5GB of data.

If you need more than 5 gigs you'll need to go with Telus (or Bell or Rogers but Rogers sucks in BC and Bell and Telus share towers (and bell are dickheads so you shouldn't do business with them)) and Telus is $125/month + tax for the above with 10GB of data.

Hope this helps.

Oh, and you'll need to be sure your UK iPhone 5 is unlocked BEFORE cancelling your contract with your UK provider. This is done by ringing their support line and explaining you need your phone unlocked because your moving to Canada. Some carriers (like O2) will do this for free, whilst others (like Vodafone, EE) will charge a small fee.

or this one

https://www.windmobile.ca/plans-and-...e-plan-wind-44

That still incurs roaming fees when your phone goes off Wind's limited network onto the Rogers network.

Tweed in your OP you said you'd be based in Vancouver for one year. Posters have provided you with several options.

Based on your call & data usage I think the mobile/cell phone plans available in Canada are expensive compared to the UK, therefore, you could also check UK providers before you leave. such as

https://www.worldsim.com/

https://www.worldsim.com/tariffs-roamfree/

https://www.worldsim.com/support/roamingpartners.aspx

Why would you use a roaming SIM in your country of residence? That's an awful idea for many reasons

1) You don't get a Canadian number with world sim. You get a US one and/or a UK one and both are Long distance for Canadians to call and even text you.
2) You are paying pay per minute, pay per text, and pay per megabyte rates for talk text and data respectively, and those are definitely higher than the local Canadian provider rates. 40c a minute! 46c a text 12c a megabyte ! ! Those are all bad for local, fulltime use. And definitely not conducive to a lot of data use, which he said he wanted in his OP.

Koodo wins my vote as well. We use prepaid ('PAYG') - pay $15 a month for unlimited texts (Canada and international) plus top up with $30 for 1 Gb of data and $25 for 500 minutes Canada-wide talk whenever we need it (these talk and data boosters don't expire after a month).

We make international calls from our mobile via LocalPhone - ridiculously cheap.

I think you'll find it hard to get a 1-year contract, so PAYG might be the way you have to go.

I use to have a 6GB deal with rogers and they have data in all cities i visited in canada as a trucker and i visited most, their LTE should now be in most cities too. Unlimited talk time with them too. But those packages may not be available now.