Since Over Sea, Under Stone is only a few years older than my mother it’s managed to accumulate quite a few covers! Now when it comes to the English covers I’m not sure to what country they belong to, US, UK, Canadian, or otherwise since many reprint the same covers but the following nine are all the English covers and then we’ll get to the other languages I could find covers for. The first cover I'm going to talk about is the paperback cover that I read for this book. It's a fairly newer cover that was released in 2000 I believe and it features a man leaning against a stone. Now this isn't the way I pictured the standing stones in the story and the man doesn't look like any of the characters described (though I'm guessing he's supposed to be Gumerry) so while I like the style of the illustration, I'm not really fond of this cover.
The blue cover with the three kids and Gumerry on it standing next to some stones (again, not like I imagined) has a 1960's look to the illustration so I believe it may be the first edition from the UK but I honestly don't know for sure. The reddish Puffin cover is kind of cool because it's so different but those eyes at the top are creepy! I do like all the different images mixed together and how Trewissick seems to flow right into the grail though. Again, I can't say for a 100% but I have found information online that says this is the 1982 Australian edition. It's kind of plain and the grail doesn't look as it's described but I do like the swirly green background of the 2007 paperback cover which was reprinted slightly different this year.
Some say 1989, some say 1990 for the cover with the three children in the attic after they first found the map. I don't particularly care for the cover but it really reminds me of paperbacks I had as a kid which was somewhat around that period of time. I do have to say it's definitely the most different of all the covers because it's the only one that shows this particular scene from the book. The 2004 Aladdin (love their books!) paperback shows the bad guy I believe on the night the children and Gumerry go to investigate the stones for clues. Again, it's not one I really like. I'm not sure where the next one comes from or what year but I think it's a hardcover. It's a really interesting cover though a bit dated. It is the only English cover with Arthur but the stones are the same as the ones on the UK first edition only lit up from the sun this time.
The next one is another Puffin paperback cover and it's so odd! This is the best grail so far but it's doing something very odd to the bad guy's head! He sure is ugly though. I'm not sure what the runic alphabet in the background is supposed to represent though. I'm not sure why the golden 2005 Puffin paperback appeals to me but I do like it despite the fact it doesn't really do anything for the story.
The Swedish cover isn't the first to show a bird of prey on the cover (though I have no clue why since there isn't one in this book) but it is the first one to have a man with no shirt on the cover. I really don't like this one and is it just me or does it look there is four kids on the cover instead of three? The translation for this cover is Overhead Under Rock or Above the Sea Under Stone. I was a little disappointed that I couldn't find a clear version of the Spanish cover (Over the Sea, Under the Earth) but I do think the main part that you can see is neat which is the map.
The Norwegian cover I found is kind of plain with only the stones and the grail and the title translates to Light Knight. Now the Japanese cover is cool. It's managed to make all the characters look foreign so the book appears almost manga-like but I'm still really impressed with it. The title it’s mainly known as is Cornwall’s Holy Grail.
The Italians must love this book since I was able to find several different cover for it. The first Italian cover (which translates to Above the Sea, Beneath the Earth) I found is actually a twofer! It's the same book, just different cover drawn in pretty much the same style which I don't really like but it's still interesting. The second Italian cover is really neat since it's got the good and the evil guys battling over the grail. Plus, I think it's just beautiful even if it does remind me of Lord of the Rings... I recognize the children and the grail in the first cover but that's definitely not how they found the grail and I'm not sure who that creepy green skinned person is supposed to be with the blue hat.
The German title translates to Before the Tide Comes In and it's the first one I've found that has real kids on the cover. I definitely wouldn't pick those to be the characters however! Plus, is that a castle up on that cliff? Where did that come from?! The second German cover is slightly better though it's a little too blue. It does at least depict a scene from the book and the grail looks right.
I was also able to find a Finnish cover (it translates perfectly into the English title) for Over Sea, Under Stone and it's another one with the bird of prey (who is not in the story) set in the stones. Not sure who the barely there faces are supposed to be though. The Dutch version (Above Sea, Under Stone) is quite similar even without the faces and set during the day. The shadow of the hand is interesting though. I actually can’t find any French covers for this one and I’m sure there are some as well as other languages too but I looked for as many as I was able.