The company said its majority-owned mine remained on track to produce between 140,000-175,000 tonnes of copper this year, with more than 80% expected in the second half.
The US$6.3 billion development is expected to ramp up to more than 300,000t of annual copper production over the next few years, with First Quantum set to provide more details in its second quarter results next month.
"This first shipment, at copper concentrate grades consistent with plan, is a significant milestone in the ramp-up at the project," the company said.
It said the Panama-flagged Missy Enterprise left the Punta Rincon port at Cobre Panama on June 19 with a total load of 31,377 wet metric tonnes of copper concentrate as per the captain's draft survey.
The next vessel, the Clarke Quay, had already docked and was expected to load about 44,000wmt over the next few days, with ongoing vessels due every 2-3 weeks.
The company has said it was "working closely with government" to resolve issues surrounding Cobre Panama's mining contract extension, which president-elect Laurentino Cortizo says he will review.
First Quantum says the copper market outlook continues to show a supply deficit "in the next few years" and it is also assessing developing its Hacquira copper project in Peru and the Taca Taca copper-gold-molybdenum project in Argentina.
Its shares were trading above C$19 a year ago but fell as low as $9.45 in January. They gained 3.26% yesterday to close at $12.34, capitalising it at $8.5 billion (US$6.4 billion).