Seventeen crew members were arrested during the operation off the coast of second city Alexandria, the military said on its Facebook page.
It did not disclose the identities of the migrants or of the crew, but said they were taken to a naval base in Alexandria. It also did not it say when the operation took place.
Pictures posted online by the military showed men, who appeared to be African, sitting in a docked boat or on the ground of what seemed to be a harbour.
The military said a navy patrol spotted the fishing boats off the Alexandria coast, stopped the vessels and boarded them for inspection.
"In addition to 17 crew, 228 people of different nationalities who were trying to reach Europe illegally were found on board," the statement said.
The UN refugee agency UNHCR yesterday said 366,402 migrants had crossed the Mediterranean to Europe this year, with 2,800 dying or going missing en route.