The U.S.-based airlines says the jobs, which include customer service agents and ramp agents, will now be outsourced.
There will be 95 jobs affected in Toronto; 84 in Vancouver and 61 in Calgary.
The cuts will become effective in three months.
United says the announcement does not have any effect on the number of flights the airline operates in Canada.
Company spokesperson Christen David said in an email that the cuts were difficult but necessary decisions for the airline to run a "more efficient and financially sustainable business."
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