British youngster Chloe Johnson drowned in a swimming pool while on holiday in Egypt, according to the travel company First Choice.
The six-year-old from Forest Hill, south-east London, died in a waterpark at the Coral Sea Waterworld Hotel in Sharm el-Sheikh.
A Foreign Office spokesman said: "We are aware of the death of a British national in Sharm el-Sheikh on 17 May. We are providing consular assistance to the family at this difficult time."
First Choice said it would carry out a "full and thorough investigation" in partnership with the hotelier.
A spokeswoman said: "First Choice can sadly confirm that a child has died while staying at the Coral Sea Waterworld hotel in Egypt. The incident occurred in a pool in the hotel's waterpark.
"Our thoughts and condolences are with the family at this extremely difficult time. The British Consulate were immediately informed and they are now working with our dedicated resort team in Egypt, to offer every assistance possible to the family in resort.
"In partnership with the hotelier, our resort team are working to understand how the incident occurred, and we will be carrying out a full and thorough investigation. At this time our priority is to provide support to the family."
Coral Sea Waterworld described the girl's death as a "tragic accident" in a message on its Facebook page.
According to the Coral Sea Hotels and Resorts website, the Coral Sea Waterworld Hotel is "a magnificent resort leaving nothing to be desired" and is "set amid colourful landscape gardens and the resort two pools".
The large resort has almost 370 rooms and a "waterpark brimming with pools and slides".