Davina the dolphin has successfully been released into the sea and is "safe and well", an RNLI spokeswoman has told ITV News.
Once she had been stretchered onto a lifeboat, Davina was transported from the sandbanks of the River Dee to deeper waters at Rhyl Flats.
Watch the Flint and Rhyl RNLI lifeboat volunteers and British Divers Marine Life Rescue take Davina to safety:
The dolphin that got stranded on sandbanks in the River Dee, Chester, is being returned to sea.
Initially named "Dave" by rescuers and then re-named "Davina" after being identified as female, the dolphin was rescued by volunteers from the Royal National Lifeboat Institution this morning.
RNLI lifeboat operations manager Alan Forrester said: "She will probably be much too heavy to lift aboard Rhyl RNLI lifeboat so Rhyl will escort us out to sea.
"The dolphin will be released around the North Rhyl Flats as, if it is set free in any shallow waters, there are fears it will become stranded again."
A dolphin that was spotted swimming in the River Dee, Chester, is set to be returned to open waters.
It is believed the mammal "was probably chasing fish in from the sea and then got caught up in the tidal system" when it became stuck in the river, according to a marine charity.
The Royal National Lifeboat Institution said the dolphin was stranded this morning and has now been taken by boat to the Irish Sea where it will be released.
A dolphin spotted swimming in the River Dee "was probably chasing fish in from the sea and then got caught up in the tidal system," according to a marine charity.
Stephen Marsh, operations manager at the charity British Divers Marine Life Rescue, said tides at this time of year can be both very high and very low and that is probably confusing the dolphin, which is more used to much deeper water.
Mr Marsh said such an event is quite rare, adding that they would step in to take it back out to sea if it does get into trouble.
However, he said it looks healthy and they hope it will find its own way out.
Moving footage has emerged of a dolphin that strayed into a Welsh river and into English waters in Cheshire.
The footage is understood to have been captured on Monday at Connahs Quay Docks in Flintshire.
From there the dolphin was seen further up the river in Saltney, near Chester and was most recently seen near Chester Racecourse.
Marine experts think the common dolphin, which is usually more at home in the deep seawater of the Bay of Biscay, must have been chasing fish up the River Dee in North Wales.
The dolphin is being monitored by a marine charity in case it gets stranded on a sandbank.
A dolphin is being monitored by a marine rescue charity after swimming miles up the River Dee in Flintshire.
The mammal was spotted by the public in Connah's Quay docks on Monday but swam up river to Saltney, near Chester.
It became stranded briefly on Tuesday afternoon after turning to make its way to Flint and back towards the sea.