The Britons - three of whom were identified by the Foreign Office last night as Andrew Dellar, from Sussex, William Love, from Glasgow, and Karen Salt, (whose address is yet to be released) - were on a hiking tour through one of Oman's most popular recreation areas in Wadi Bimaah, the so-called Snake Gorge, near Rustaq.
The seven victims, who also included two Americans and a Dutch woman, were among 26 people on the trek. One other person was injured.
Rescue teams are still searching for the body of one missing Briton. Another was taken to hospital and is said to be in a stable condition.
"The victims were terribly unlucky," said a British Embassy spokesman in Muscat. "There is always a risk when going on these excursions, but it was a popular tour and people don't really expect any danger.
"There are only 6,000 Britons out here in Oman," he said. "This has deeply upset everyone." He said British Embassy staff were working closely with the Royal Oman Police and other Omani authorities.
Officials said that the worst floods to hit Yemen in 30 years have killed more than 300 people and made thousands homeless. The floods began in mid-June, caused by unusually heavy rains. The Yemeni President, Ali Abdullah Saleh, has said the damage is estimated at $1.2bn (pounds 0.8bn).