A regional eSIM is a straightforward idea with one design trap, and the trap is the country list. Everything else about it is a question of whether you are the traveller it was built for.
What a regional plan does
Instead of a plan for one country, you buy a plan that works in a named set. You install it once, and when you arrive somewhere on the list, the phone connects to one of the partner networks there. Cross a border and it connects on the other side.
For anyone who has spent an afternoon of a holiday hunting for a SIM shop in an unfamiliar town, the appeal is obvious. There is nothing to find, nothing to register and nothing to explain. The plan is already in the phone.
The trap: the country list
The name of a plan tells you less than you think. A product branded for Africa may cover twenty countries and leave out the one you are crossing into, because the exclusion is a commercial decision rather than a geographic one.
So the only way to buy well is to read the list, country by country, against the itinerary you have actually booked. If your route is South Africa, Namibia and Botswana, check all three, not the first one and the general name of the product.
Two related things are worth checking at the same time. The validity period, since a plan that lasts fifteen days is no use on a three week trip, and whether the plan covers the countries you will merely transit, since an airport stopover is not usually a problem but a long road transfer through a fourth country might be.
When it makes sense, and when it does not
The regional plan earns its price on a trip that moves. Three countries in one journey, or a road trip where the borders come every few days, is exactly what it was designed for.
It is the wrong purchase for a single country. A national plan is cheaper per gigabyte and its coverage is tuned for the networks that actually exist where you are going, rather than for a lowest common denominator across a set. If you are spending two weeks in Morocco, a Morocco plan is the better buy.
There is a middle case worth thinking through. If you are crossing one border and spending a good while in each country, two single country plans can cost less than one regional plan, at the price of installing a second profile mid trip. Whether that trade is worth it depends on how you feel about doing admin on holiday.
Crossing a border, in practice
The moment that decides whether a regional plan was worth the money is the border, so it is worth knowing what actually happens.
On a land crossing you will lose signal as you leave one country and pick it up again on the other side, sometimes within a minute and sometimes after twenty kilometres of no man’s land. Nothing needs to be done. There is no setting to change and no plan to reactivate, and that is the whole advantage over a stack of national SIM cards.
Two things do occasionally go wrong. The first is that the phone holds on to the old network for too long, showing no service when a usable one is available. The standard fix is to switch airplane mode on and off, which forces the phone to look again. The second is that data roaming has to be enabled on the travel line for any of this to work, which surprises people who have spent the trip keeping roaming switched firmly off. On a travel eSIM, roaming is how the plan works rather than something to avoid.
What to check about speed
A regional plan connects you to partner networks, and the partner is not always the fastest network in the country. Where a country has three operators, a regional plan may hold agreements with two of them, and which one you get is whichever the phone finds first.
In practice this matters less than it sounds for messaging, maps and browsing. It matters for video, and for uploading photographs, which is worth knowing if those are part of your day. If speed is genuinely important, a local SIM gives you access to the full set of networks in that one country.
The neighbouring countries question
One more thing worth being clear about, because the name of our own continent-level thinking can mislead.
Morocco, Egypt and South Africa are not neighbours. A trip that includes more than one of them involves flights, continents of distance, and very different network landscapes. A single plan covering all three is a multi region or global product rather than a regional one, and it is priced accordingly.
What usually makes sense for our three countries is a plan for the country you are in, and a second plan only if your route really does continue on the ground into a neighbour, such as South Africa into Namibia or Botswana, or Morocco into the Spanish enclaves.
If your trip is staying within one country, what an eSIM is covers the basics, and the country pages for Morocco, Egypt and South Africa show what is available for each.