If I have my 3 children's savings in 3 tax-free savings accounts here in the UK, how should I move the money (and any FX rate 'profit' should I move it after landing) to a Canada bank without incurring capital gains tax?

if this is the government voucher scheme, I'm not sure you can move it. We have 2 of these and just registered a change of address with them.

It would them be up to the children to move it once they come 'of age'.

Proper cash savings, not the voucher scheme...

Unless they need it in a hurry, do you want to exchange it at $1.70. Who knows what it will do in a few years. Guess it depends how much there is as to whether it is a concern.

I'd echo that. Change the contact address for the accounts to a parent or friend and wait a while. The exchange rate in recent months has been pants. Wait to see if you are staying

Do I have to pay capital gains tax on the FX profit?

Depends on the amount of gain and if the accounts are in the children's name there and go into same here. If I recall correctly, if the gain is under $200 then no for anyone. Are you talking about big sums?

There's always premium bonds in the UK - you can still have these when living in Canada and don't get taxed on any "winnings" at all.

If the accounts are in your childrens' names you would need to report any capital gain on their tax returns. Assuming they have no other income, in any one year they can realize $20,000 FX profit ($10,000 taxable capital gain) for each child effectively tax free. This is because every person who files a tax return is entitled to a tax credit equivalent to the tax due at the basic rate on the first $10,000 of taxable income.