The migrants died as they were trying to cross from the country's western coast to Italy.
The migrants were found in two separate operations.
In the first operation, the coastguard found 11 bodies and 83 survivors off the town of Sabratha, while in the second, the coastguard rescued 180 migrants on two inflatable boats near the town of Zliten.
The migrants were believed to be from various sub-Saharan African countries.
Libya was plunged into chaos following a 2011 uprising, and remains split between rival governments in the east and west, each backed by an array of militias.
Libya has since been a frequently used route to Europe for migrants fleeing poverty and conflicts in Africa and the Middle East.
More than 600,000 crossed the central Mediterranean to Italy in the past four years, the vast majority from Libya.
