Egypt is a visa country for most visitors, and the good news is that the system is simple: almost everyone who needs one can get one either online before flying or at the airport on arrival. The complication is that there are three or four different routes in, each with its own rules, and the one that applies to you depends on the passport you hold and on where you are actually going.
Start with the two facts that are not negotiable. Your passport must be valid for at least six months from the date you arrive, and you need a visa, a visa on arrival, or one of the exemptions before passport control. Everything else is detail.
The three ways in
The e-visa is the tidy option: applied for online, paid by card, issued electronically, and it can be single or multiple entry and for longer than a month. Apply some days ahead, print the approval, and take it with you, because airlines and border staff ask for it.
The visa on arrival is the traditional option and still the most common. You buy it at a bank window in the arrivals hall, paying in a hard currency, before you join the passport queue. It is normally a single entry for 30 days. There is a second, conditional route: travellers holding a valid and used visa or a residence permit from the Schengen area, Australia, Canada, Japan, New Zealand, the United Kingdom or the United States, or a residence permit from a Gulf state, can be issued a 30-day visa on arrival, provided the permit is valid for at least six months from arrival and they have a return ticket and funds for the stay. Citizens of a small list of countries, including Afghanistan, Ethiopia, Iran, Israel, Mali, Niger, Palestine, Sudan and Syria, cannot use that route.
The third option is a visa from an Egyptian embassy or consulate before you travel, which is what you do if you cannot use either of the others, or if you need something unusual: a long stay, multiple entries, work or study.
The Sinai stamp, which is a fourth route
If you fly into Sharm El Sheikh, Saint Catherine or Taba and stay inside the Sinai resort areas, you may be admitted without a visa at all, for up to 15 days, with a free permission stamp. For citizens of the European Union, the United Kingdom and the United States this is documented as applying to stays within Sharm El Sheikh, Dahab, Nuweiba and Taba, without leaving those areas.
Two warnings. It does not cover the mainland: Cairo, Luxor, Aswan and the Nile are outside it, and so is Hurghada on the mainland Red Sea coast. And it does not apply to every nationality: nationals of a long list of countries, including India, Indonesia, Pakistan, the Philippines, Lebanon, Morocco and Kenya, are excluded from the programme and need a proper visa. If you are planning a week in Dahab and then a flight to Cairo from Sharm, buy the full visa.
At the airport, and at the border
Arrival is a sequence rather than an ordeal: the arrival card, handed out on the plane; the bank window for the visa if you are buying one; passport control; baggage; customs. Keep the slip or stamp you are given, because it is your proof of lawful entry and you may be asked for it when you leave.
Egypt also has currency rules worth knowing before you meet them. Large amounts of foreign cash must be declared on entry, and there are limits on how much Egyptian currency you may take in or out of the country, so declare anything substantial, keep the receipts from your exchange transactions, and do not plan to leave with a suitcase of pounds. The Egyptian pound is also difficult to buy outside Egypt, which is why most people arrive with dollars or euros and change money on the ground.
Extensions, overstays and the rules that change
A 30-day tourist visa is often not long enough for a slow trip, and extensions are available inside Egypt from the passport and immigration offices. Apply before the current permission runs out, take your passport, the entry slip and photographs, and expect a fee. An overstay, by contrast, is treated as a serious matter and is far more expensive to resolve than to avoid.
One last piece of advice that applies to every guide on this site: visa fees, exemption lists and the fine detail of the Sinai programme are set by the Egyptian authorities and change without much notice. Check the official portal and the current travel advice for your own nationality in the week before you fly, rather than relying on a page written last year, including this one.
The short version: passport with six months on it, decide between the e-visa and the airport, take hard cash for the fee, and be careful with the Sinai stamp if your itinerary leaves the peninsula. Everything else is paperwork you can do in advance at a kitchen table.