The boats for Mayor Bill de Blasio’s Citywide Ferry Service are coming down the assembly line.

Two southern shipyards have begun building the 19 aluminum-made vessels that will eventually serve the municipal ferry network, expected to launch in summer 2017.

The city is announcing on Thursday that components have begun arriving at the contracted Metal Shark and Horizon shipyards, in Louisiana and Alabama, respectively, as some 200 workers begin piecing together boat frames.

“We are moving full steam ahead and bringing modern ferry boats, outfitted with the latest technology and safety features, to our waterways,” said Mayor de Blasio in a statement. “This new fleet will help us connect commuters and visitors alike to neighborhoods throughout the city,”

Maria Torres-Springer, president of the New York City Economic Development Corporation, which is overseeing the ferry service, said that boats should arrive “early next year.” Service testing is expected to start shortly thereafter.

“With vessel construction now fully underway, we’re one step closer to bringing fast, affordable ferry service to neighborhoods across the city,” said Torres-Springer in a statement. “We can’t wait for New Yorkers to see these modern and efficient boats.”

Each 85-foot-long boat will have the capacity to carry 150 passengers along with bicycles, strollers and wheelchairs. The ferries, which the NYCEDC describes as lightweight and fuel efficient, will come with free Wi-Fi and heated decks.

Hornblower, which will operate the service, will charge $2.75 for a one-way ride. The city originally aimed to meet the cost of a subway ride with hopes to integrate with the MetroCard. That would have potentially allowed for free transfers into subways and buses.

But that goal was dashed because the state-run MTA is in the early stages of replacing the MetroCard with new fare payment technology. The NYCEDC said it would pursue integration when the MTA phases in new technology, still several years away.

Next summer will mark the Phase One service launch and will utilize 12 of the new ferries at three routes: Astoria, South Brooklyn and Rockaway, with stops in Manhattan. Service will be expanded into the Bronx and along additional landings on the Lower East Side a year later, in 2018, to meet an estimated 4.6 million passenger trips per year.

“Come summer 2017, millions of New Yorkers will have a new way to ‘Work, Live, Play’ on our growing and thriving waterfronts, and we are confident in both shipyards’ ability to deliver the next big critical piece of New York City’s transportation network on schedule,” said Cameron Clark, Hornblower’s Citywide Ferry project manager.

Staten Island will have to wait for its fast-ferry service. A proposed, unfunded route for a third expansion would link Coney Island to Staten Island’s Stapleton neighborhood to lower Manhattan.