John Mullan (49), his 14-year-old son Tomás and six-year-old daughter Amelia died after their car skidded off the road into the water at Lough Foyle late on Thursday.
The family of four had been on their way back from a day out in Derry when Mr Mullan lost control of the car at Three Trees in Quigley's Point. It skidded across the road and plunged into Lough Foyle shortly after 10pm.
Mr Mullan's wife and mother of their children escaped from the sinking car and was rescued. Nurse Geraldine Mullan was taken to Letterkenny University Hospital but her injuries were said to be not serious.
Gardaí are investigating the possibility that road resurfacing work may have contributed to the accident. Stormy weather conditions may also have been a factor.
The funeral of all three will take place in Moville parish church at 11am on Monday. The event can be streamed online.
In keeping with Government guidelines on Covid-19, only a small number of people can attend the service – however, hundreds of people are expected to line the route from the family's home to the church.
Among those who will attend the funeral mass will be Mrs Mullan's family, who will travel from her hometown in Williamstown, Co Galway.
The family have asked for donations to Laura Lynn Children's hospice in lieu of flowers.
