The Russian consulate in Hurghada said the submarine, which belonged to the Sindbad hotel in the city, had 45 Russian tourists on board in addition to crew members.
The submarine was out on a regular tour to view coral reefs and it sailed off about 10am on Thursday and sank when it was about 1km from the shore.
The consulate said four people had died but did not specify if they were Russian.
"According to initial data, most of those on board were rescued and taken to their hotels and hospitals in Hurghada," the consulate said.
The fate of several tourists was still being clarified, the consulate added.
Local media reported that rescue teams had saved 29 of the 45 passengers aboard the submarine.
Emergency crews were able to rescue 29 people, according to a statement released by the Red Sea governorate.
The submarine had carried 45 tourists of various nationalities.
It was not immediately clear what caused the submarine to sink.
The Red Sea, renowned for its coral reefs and marine life, is a major hub for Egypt's tourism industry, which plays a critical role in the country's economy.
In November, a tourist boat capsized off Egypt's Red Sea coast, killing four people.
with AP
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