A four-member crew left the ISS early Tuesday on a SpaceX Dragon spacecraft.

The two NASA astronauts whose return to Earth was delayed for months are on their way home.

Sunita “Suni” Williams and Barry “Butch” Wilmore left the International Space Station on a SpaceX Dragon spacecraft early on Tuesday and began an approximately 17-hour journey toward a splashdown off the Florida coast.

NASA astronaut Nick Hague and cosmonaut Aleksandr Gorbunov were also onboard the craft as it undocked at about 1:05 a.m. ET.

A SpaceX Crew Dragon capsule carrying Butch Wilmore and Suni Williams, two veteran NASA astronauts who have been stuck on the International Space Station for nine months, and Roscosmos cosmonaut Aleksandr Gorbunov and NASA astronaut Nick Hague, manoeuvres in space following undocking from the ISS to begin a journey to return to Earth March 18, 2025, in this still image taken from video.

Williams and Wilmore had in June 2024 performed the first astronaut-crewed flight of Boeing’s Starliner capsule. What was expected to be a weeklong trip to the ISS instead turned into a nine-month stay.

Their return spacecraft early on Tuesday maneuvered in space, moving above and behind the station, before firing a series of departure burns that sent it back toward Earth.

Astronauts are seen inside a SpaceX Crew Dragon capsule carrying Butch Wilmore and Suni Williams, two veteran NASA astronauts who have been stuck on the International Space Station for nine months, and Roscosmos cosmonaut Aleksandr Gorbunov and NASA astronaut Nick Hague, after the capsule undocked from the ISS to begin a journey to return to Earth March 18, 2025, in this still image taken from video.

NASA said it expected the return trip to end at about 5:57 p.m., when the Dragon is scheduled to splash down off the Florida coast.

This is a developing story. Please check back for updates.

ABC News’ Matthew Glasser and Mary Kekatos contributed to this report.