If I return to Canada later, can I get departure tax I paid earlier refunded or credited?

Potentially, yes, if you still own the same property, or something that stands in its place, when you come back. The Income Tax Act includes a mechanism that lets a returning resident adjust the tax consequences of departure tax paid earlier on property they still hold, recognizing that Canada already taxed the increase in value up to your departure date and shouldn't tax that same increase again once you're back and subject to Canadian tax on an ongoing basis.

This isn't an automatic refund that shows up without action — it generally requires an election, made in connection with your return for the year you become a resident again, and applies specifically to property that was subject to the original deemed disposition and that you've kept through the period of non-residency. Property you sold while abroad, or acquired after you left, doesn't fit this mechanism the same way.

Because this involves matching up specific property across two residency changes, sometimes years apart, keeping good records of what you owned, its departure-date value, and what happened to it while you were away makes claiming this relief far more straightforward when you do return.