One actor who can play 14-15, and then 17-18 a year later, is doable, given how boys mature in their mid teens. 

If two brothers,perhaps their grandfather could play elderly Caspian in SC?

I vote One. Try to make it with one actor for his major appearances.

Still, even though I agree two actors for Caspian would be jarring enough (3 if you count old Caspian; 4 if you count Caspian with his Nurse!), maybe not as much as having a teen Caspian being played by a 25-year-old actor. That's been done twice. In both BBC and Walden. I hope that circumstance is avoided entirely this time.

But one thing makes sense to me: In my own view, Caspian's age depends on the 2 things: the age of the pevensie actors, and how long a break there is between Caspian and Dawn Treader.

Caspian's actor should be around Peter's actor's age: 3 years older than Edmund's actor. (Caspian is 2 years older than Edmund in 'Caspian' while he's 4 years older than Edmund in Dawn Treader).

Also I don't think it matters that much that Caspian look older. It's like Reepecheep's height change: It's cool, but was made to suit the book's story at that moment. 

So, one actor. 🙂

 If the filmmakers were very lucky, they could pull it off with one, but if I was casting, I would always have two young men cast. I think its so important to connect with the "childhood" aspect of Caspian while still allowing him that "coming of age" story. 13-14 would be perfect for Caspian. I've always seen him as 18-19 for Dawn Treader, but of course its impossible for him to age quicker than Edmund and Lucy. I think for Dawn Treader, its really important to feel that Narnia has a real King in charge, otherwise the power dynamics between the former Royals and Caspian might feel a bit odd. 

Posted by: @jfg-ii

Caspian's actor should be around Peter's actor's age:

This is one of those things where I'm not sure I even agree with Lewis's own timeline based on the behavior of the characters in the books. I really feel Caspian needs to be AT LEAST a full year younger than Peter, and I would prefer Edmund's age. (On the "official timeline" Caspian is the same age as Susan.)

And even though he's aged, what, 3? 4? years according to his comment to Lucy in the Dawn Treader, I'd prefer it be a full 10 years because he's at the point where he's courting (and marries Ramandu's daughter). 

So for me personally, I'd prefer a young teen in PC and a very late teen/early 20s for DT. Yes, it's a departure from what's stated in the book, but I feel more appropriate to the character's behavior. 

Hmmm, I think I would prefer the same actor for the majority of Caspian's appearances, but I would like for them to cast a younger boy to play Caspian for the scenes when the reader first meets him in Prince Caspian, when his Nurse is still caring for him. Reading the book, he seems more like he's about six years old (Lewis describes him as a very little boy), and I just don't think those scenes with the Nurse and Miraz would work the same with a 13-14 year old actor.

I actually rather like the idea of a 15-16 y/o King Caspian in VDT; it's not that uncommon to find teenaged monarchs in history books, but it's not something you see on film very often. If they jump to filming VDT right after PC, though, the actor may not have time to have aged very much. (Hence this discussion. )

The Logos Theatre, if you'll pardon my mentioning them again, has successfully used a small boy and an older boy, almost seamlessly, to play the same character, both in Prince Caspian (a few years ago, and back in rehearsal currently for a repeat season),and HHB (audience chuckled at the simple method of having little Shasta bob down behind bench to get something, and main actor then come up and take his place!)

I don't see any problem with its being done on film, a small child with a hairdo that looks enough like the early teen Caspian, to play the scenes with Nurse. What I don't want is a 13 year old acting like a 6 year old for those scenes.

I guess I should have made the topic title "Two Caspians or Three."  

Technically, it should be four Caspians. Remember the old in The Silver Chair?

I remember when the BBC version of Narnia was first shown on TV — when I was in early primary school and had only recently finished reading all seven of the books — I could understand why they used a different actor for Caspian in The Voyage of the Dawn Treader, on account of him being three years older than he was in Prince Caspian, but I thought they could have done a much better job of trying to find someone slightly older who actually looked reasonably like the first Caspian actor. As it was, VDT Caspian not only looked older than 16 or 17, he was blond while the original younger Caspian was dark haired!! It made it a bit hard to believe he was the same character.

(Canonically, Caspian IS blond, whatever Walden/Disney may think — Lewis mentions that more than once. Same with Lucy, actually. As a blonde Narnia fan myself, I object to seeing my favourite characters continually, er, darkwashed. )

My thought is that it would be better for Netflix to use the same actor for Caspian in the main part of PC and the whole of VDT — ideally, go for someone who's about 15, so that he can believably be made to look 13-14 in PC and 16-17 in VDT.

I do also agree with the suggestion from others here that there should also be a young boy actor in the early Caspian scenes in PC so that we get to see Caspian as a very young child listening to his nurse's stories. I'm imagining we could cut to flashbacks from LWW, and also from MN if they make that one first, as Nurse is talking, and then shortly afterwards little Caspian starts innocently telling Uncle Miraz that he wishes he could have lived in the Old Days...

That whole scenario is crucial for setting up the rest of the story — they could actually open the series/film of PC with it, before cutting to the opening of the Pevensies' story at the railway station — and Caspian really needs to be "only a very little boy" (to quote the book) at the time for it to make sense, especially to capture his wide-eyed wonder at these marvellous stories of Old Narnia, and then his horror when he discovers his nurse has been sent away because of what he said to Miraz. That, in fact, is one thing the Focus on the Family radio play version of PC messes up — they use the same voice actor for Caspian throughout, so at his first "appearance", when he starts talking to his uncle about "the Old Days" and gets into trouble for it, he has the already deepish voice of a teenager. It just sounds completely wrong for that scene.

On top of that, yes, we definitely DO need another actor to play Caspian as an old man in The Silver Chair. Apart from the fact that it would be very difficult to make "teen Caspian" from PC/VDT look convincingly elderly, it's absolutely essential to the plot that he's not recognisable as the Caspian that Eustace once knew! So for my preference, that makes three Caspian actors: young Caspian for early scenes in PC, teen Caspian for PC/VDT, and old Caspian for SC, with teen Caspian having a cameo at the end when Aslan raises him from the dead.

(Oh yes, there's another incongruity from the dear old Beeb. As I mentioned, the BBC's VDT uses a different actor from the one they used in PC. But at the end of the BBC's version of SC, when Caspian comes back to life in Aslan's country and he and Eustace greet each other, he comes back as the younger actor, the one from PC — who looks completely different from the bloke that Eustace knew from his voyage on the Dawn Treader!!)

It might be an idea to cast an "older" actor, like in his 20s, who can look older and younger. It might have to be a case of ageing Caspian up when it comes to Voyage of the Dawn Treader, but if they want the same actor for both films/series, then this would probably be the best approach.

And as people have already stated, they'll need an actually old actor to play Caspian in The Silver Chair.

Posted by: @rillianix

It might be an idea to cast an "older" actor, like in his 20s, who can look older and younger.

I've thought about that, but the problem with casting a Tom Holland-type actor who's basically done aging is you can end up creating the opposite problem in regards to PC and VDT — instead of it looking like Caspian has aged three years when it's only been one for Lucy and Edmund, he'll look about the same while the Pevensie actors will likely look older, in effect shortening the perceived distance between their ages.

I also feel like we've already done this with Ben Barnes, and while he looked cool with his beard in VDT, I really don't want them to cast an actor old enough to grow a beard to play Caspian again.

I think what I would suggest is that they cast someone about 15-ish and give him a "childish" haircut (messier, bangs) for PC and then a more grown up, kingly haircut in VDT. That can make a lot of difference in someone's appearance, so at least there will be a visual jump between PC and VDT even if the three year age jump isn't completely believable.

That's a good point. I kind of enjoyed the look a few of the characters, mainly Timothee Chalamet had in The King (2019), which would be interesting Caspian X. Not that I'm suggesting Chalamet of course. Just the look.

@rillianix, I do like that look, actually, though a blonde Caspian might better help differentiate the Netflix version from Ben Barnes' version. 

  I lean more towards one person to play Caspian in PC, VDT, and the end of SC. The idea of having a 20 year-old sounds pretty good (actually Ben Barnes was 20 years old in Walden's PC), but he should still look like a 'boy-king' in VDT.

Posted by: @courtenay

(Canonically, Caspian IS blond, whatever Walden/Disney may think — Lewis mentions that more than once. Same with Lucy, actually. As a blonde Narnia fan myself, I object to seeing my favourite characters continually, er, darkwashed. )

I can understand why anyone would object to seeing their favorite character turned into a different hair color (though I'm not too worried about it). For instance, if a Narnia film or series adaption turn my favorite character Emeth into a light blond, I would totally flip out!  

Anyhow, Caspian as a blond is a thought. Though there are different shades of blond. I used to be a light blond when I was a little girl. Then as I got order, it darkened. So I would be curious what shade of blond they might do for Caspian.

I'm actually not too worried about how they might do Caspian's hair color. Even if they went with a dark blond for Caspian, I think it will still count for something if they do the character right.

So I would say one Caspian, though they might have to do three- a little boy for the first half of PC, a youth for second half of PC, VDT, and third act of SC (where he's resurrected), and an old man for the first half of SC.