Egyptian Red Sea liveaboards prowl the waters from the tip of the Sinai Peninsula, roughly 350 km south of Cairo, down nearly as far as Sudan, an area about 400 km long. It's an inexpensive way to experience world-class reefs in frequently calm and warm waters.
The clear waters have mild currents. December through April, water temperatures can dip to the low-70s, but the rest of the year, they range in the mid-70s to mid-80s.
A typical liveaboard itinerary will cost roughly $1,250 to $1,500 a week. Although boats vary in quality, they generally offer a high level of service, catering primarily to Europeans who expect clean accommodations. Divers accustomed to roaming Oceania on liveaboards will find the pace more relaxed, as the market attracts not just die-hard divers but also European vacationers.
Liveaboards leave from either Port Ghalib (airport: Marsa Alam MRS) or Hurghada (HRG). Some head north, taking in the tip of the Sinai (Ras Mohamed marine reserve) and the many shallow wrecks in the area. Others head south, diving the famous Brothers/Daedalus/Elphinstone reefs, or deep south, as far as St. John's Island (well north of the disputed Sudan/Egypt border). Even with scores of liveaboards, most dive sites don't feel crowded, except those reachable by day-boats serving resorts at Hurghada, Marsa Alam, and Sharm El-Sheikh.
Liveaboard itineraries are designed for one-week trips, but one can book back-to-back two-week trips on the same boat, with different routes.
Flights through Cairo are available from many North American cities. Inexpensive flights depart from most European airports, making it easy to add a week of Red Sea diving to a European trip -- or see Egypt before or after. My nonstop flight from Rome to Hurghada (a 3-hour flight) was $175 round-trip, including checked bag fees for my dive gear.