The bulk carriers Resilient Africa and Aroyat arrived in Ukraine on Saturday and were due to depart after loading almost 20,000 tonnes of wheat for Africa and Asia.
Resilient Africa left Ukraine on Tuesday with 3,000 metric tons of wheat on board.
The loadings are a test of Ukraine's ability to reopen shipping lanes after a U.N.-brokered deal to allow Ukraine to export grain collapsed after Russia pulled out.
Ukraine last month announced a "humanitarian corridor" in the Black Sea to release ships trapped in its ports since Russia invaded the country in February 2022 and to circumvent the collapsed deal.
Moscow has launched frequent drone and missile attacks on Ukrainian grain export infrastructure.
Odesa's three seaports, including Chornomorsk, shipped tens of millions of tons of grain during Russia's invasion under the U.N.-brokered deal.
Five of several vessels that had been stuck in Odesa have so far left the port, using the temporary corridor which hugs the western Black Sea coast near Romania and Bulgaria.
The Black Sea grain deal was brokered by the U.N. and Turkey in July 2022 to combat a global food crisis worsened by Russia's invasion of Ukraine. Ukraine and Russia are among the world's top grain exporters.
(Reporting by Pavel Polityuk; Editing by Tom Hogue and Miral Fahmy)
