For all their dominance on Staten Island, ferries have long struggled to muscle their way into the city’s mass transit mainstream. Experiments in Queens and Brooklyn have been held back by infrequent service, outsize operating costs and low ridership.

But the city, unfazed by past failures, is now embarking on a more ambitious plan: a year-round ferry network that will provide all-day service in the East River, starting in June.

Under the plan, to be announced on Wednesday, ferries will travel along a seven-stop route that stretches from Long Island City, Queens, to the Fulton Ferry landing by the Brooklyn Bridge, and includes Manhattan terminals at Pier 11 in the financial district and East 34th Street. During peak hours, boats will arrive at each stop every 20 minutes and travel in both directions.

The service is an attempt by the Bloomberg administration and the City Council to create a robust and viable mass transit alternative for a growing waterfront population that has struggled with clogged subway lines and bus routes that have been truncated or eliminated altogether.