In short it depends what excursions you are doing. If you are staying around the shore line, and not travelling out of Sharm then the answer is no, you do not need a Visa.
If you are planning on doing some more adventurous excursions on your holiday which require you to travel out of the Sinai Peninsula, such as Cairo and Luxor excursions, then you will require a Visa. You will also need a Visa if you go on any excursions taking you out to sea.
What Excursions require a Visa?
You will require a Visa for the following excursions:
Cairo by bus or Plane
Luxor by plane
Colored Canyon
Super Safari
All other excursions will not require a Visa.
?How do I get a Visa
Everyone must complete a landing card or immigration card , whether they are applying for a visa or not. These are often given out on the plane but one can obtain them in the Arrivals Hall of Sharm Airport. If you don’t want a visa, then simply fill in the card & write “SINAI ONLY” anywhere on the back. If you do require a Visa it will take approximately 10 minutes depending on ques to get your visa stamp
Visa's cost 25 USD so you are advised to have some dollars ready for when you land