The Vancouver, British Columbia, wireless air card maker made $3.8 million, or 15 cens a share, for the second quarter ended last month. That reverses the year-ago loss of $27.6 million, or 30 cents a share.
Sales rose to $55.2 million from $21.9 million a year ago.
Analysts were looking for a dime-a-share profit on $52 million in sales, according to Reuters Research.
But looking ahead, Sierra Wireless expects a breakeven third quarter on sales of $51 million. That is well below the 12-cent profit on $57 million in sales that analysts were expecting.
"We are very enthusiastic about the opportunities for continued growth in our core business of wide area wireless for mobile computing, as we bring our next generation products to market and continue to open new channels, CEO Jason Cohenour said in a press release.
Sierra shares fell $3.62 to $12.63 in after-hours trading Thursday.