Uma Ramalingam, 42, is thought to have been on holiday with her relative, Barathi Ruvikumar, who also died in the incident.
The women were pronounced dead after the tragic incident off the coast of Playa Paraiso on Sunday.
It was widely reported a third woman, aged 38, survived with the children, after being rescued.
A former colleague of Mrs Ramalingam, from Altrincham, Cheshire, who worked at the Royal Oldham Hospital's women and children's unit, paid tribute to the "fantastic doctor".
Olubusola Amu, consultant and clinical director of Women and Children Services at the Pennine Acute Hospitals NHS Trust, said: "She was a fantastic doctor who brought a lot of hope to the high-risk women attending the women and children's unit at the Royal Oldham Hospital.
"This is a terrible shock to everyone who knew Uma. Our thoughts are with her family at this sad time. She will be sorely missed."
A Guardia Civil spokeswoman confirmed both women were British and related, although they were unsure how.
A Foreign and Commonwealth Office spokesman said: "We are in touch with the authorities and are providing consular assistance with the families."