At Sandhurst, the prince will have the privacy he enjoyed at university
He was, until very recently, the cocooned prince. For four years, Prince William led a fairly normal existence as a university student in Scotland.
By and large, photographers with long lens kept away from the Fife town of St Andrews.
He could, in his words, "pop to the supermarket and buy some asparagus" without attracting too much attention.
When he graduated last June, he remarked to someone: "I'm going into the big wide world."
He's been there for seven months now. He's occupied his time doing some work experience and preparing for Sandhurst.
Whether or not he wants to join the Army is a rather academic question.
As a future head of the armed forces, it was always inevitable he would have to spend some time with them. The bond between the monarchy and the military is very strong.
William's following a well-worn royal path.
His grandfather was mentioned in dispatches during the Second World War; his father learnt to fly with the RAF and joined the Navy. And of course, Prince Harry's already at Sandhurst as a "guinea pig", as William has put it.
The younger brother's made it clear he's very much looking forward to the day, in a few months time, when William will have to salute Harry.
William has spent two weeks with RAF Valley mountain rescue team
There'll be early rises for William who's confessed he likes a lie-in; intensive drill sessions and gruelling physical training.
Sandhurst will also offer him something he became used to at school and university - privacy.
The Army's newest royal recruit presents them with plenty of positive publicity and a potential problem - what do they do with him once he graduates from Sandhurst at the end of the year?
To put it bluntly, he can't be deployed anywhere too dangerous.
Now in his 20s, he's so far managed to resist rushing headlong into a life of shaking hands and cutting ribbons
William knows that. He's also made it clear he doesn't want to be "mollycoddled" or "wrapped in cotton wool".
As he said in an interview last year: "If I joined the Army, I would want to go where my men went. I'd want to do what they did."
Army life is yet another stage in the development of William, a senior member of the royal family.
Now in his 20s, he's so far managed to resist rushing headlong into a life of shaking hands and cutting ribbons.
That's where his long-term future lies. What he does in the short-term is not similarly set in stone.
One can imagine Harry - the young man who enjoys running down a ditch full of mud - embracing life as a soldier for some time to come.
The King-in-waiting may well bide his time - and it could be a long time - involved in land management and charitable work
William's military career may well be measured in years, rather than decades. And then what?
When he was 30, Prince Charles spoke of needing to find a role.
It can be assumed officials are working already to ensure his son doesn't suffer a similar crisis of confidence.
William's room for manoeuvre is limited. There are countless jobs he can't touch.
The King-in-waiting may well bide his time - and it could be a long time - involved in land management and charitable work.
Another issue, whether he likes it or not - and he's bound to dislike it intensely - will be the focus, in the years to come, on who will be his wife.
There'll never again be a fairytale royal wedding here. We're all older and wiser. But there's still an expectation of a princess accompanying a prince.
One tabloid's quoted him as talking of getting married when he's around 30.
For now though, William wants to enjoy his relationship with his girlfriend, Kate Middleton, away from the glare of publicity.
In the coming weeks and months, William's focus will be on his transformation into an army officer.
If he ever has a twinge of homesickness as he masters the art of ironing perfect creases into his combat shirts - help will be at hand.
There are numerous pictures around Sandhurst of his grandmother, the Queen.