Does departure tax apply to my TFSA when I leave Canada?

No — your TFSA is one of the registered accounts excluded from the deemed disposition rule, so you don't owe departure tax on the investments held inside it simply because you stop being a Canadian resident. The account keeps its tax-free status for Canadian purposes even after you become a non-resident, and you generally don't need to collapse it or trigger anything on the way out.

Where things change is what you can do with it going forward. Once you're no longer a Canadian resident, you generally stop earning new TFSA contribution room, since room accrues to residents; withdrawals remain permitted, but making new contributions while non-resident is treated unfavourably and can attract its own separate tax consequence, so it's generally not advisable to keep contributing after you've left. The account can also be affected by how your new country of residence taxes it, since a TFSA's tax-free status is a Canadian concept that other countries don't necessarily respect.

Because the Canadian and foreign tax treatment of a TFSA can diverge sharply after a move, checking how your destination country treats it, separately from the Canadian departure-tax question, is worth doing before you decide whether to keep contributing or start drawing it down.