No, your Galaxy S21 Ultra case won't fit the OnePlus 12
The Galaxy S21 Ultra (165.1×75.6mm) and OnePlus 12 (164.3×75.8mm) differ too much for cases to be compatible.
Does a Galaxy S21 Ultra Case Fit OnePlus 12?
Last verified: March 2026
No, a Galaxy S21 Ultra case will not fit the OnePlus 12. The phones have different dimensions that make cases incompatible.
Your Galaxy S21 Ultra case will NOT fit the OnePlus 12. Here's why:
- •Body dimensions are nearly identical, but the camera cutout is incompatible (vertical-quad vs circular-triple)
| Spec | Galaxy S21 Ultra | OnePlus 12 | Diff |
|---|---|---|---|
| Height | 165.1mm | 164.3mm | Galaxy S21 Ultra +0.8mm |
| Width | 75.6mm | 75.8mm | OnePlus 12 +0.2mm |
| Thickness | 8.9mm | 9.2mm | OnePlus 12 +0.3mm |
| Camera Layout | vertical-quad | circular-triple | Different |
| Port | usb-c | usb-c | Same |
Button & Port Alignment
- •New phone has alert slider — old case has no cutout for it
Since your Galaxy S21 Ultra case won't work with the OnePlus 12, here are the highest-rated cases that will:
Ringke
Ringke Fusion-X MagSafe for OnePlus 12
$14.99
Ringke
Ringke Fusion-X for OnePlus 12
$12.99
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Size Comparison
Wireless Charging & MagSafe
Wireless chargers work with both phones, but magnetic snap varies.
- Both devices support wireless charging. Standard Qi/Qi2 chargers work with either phone.
Galaxy S21 Ultra
Qi only
15W max
OnePlus 12
Qi only
15W max
MagSafe cases are NOT cross-compatible between these devices — the case body is shaped to each phone, even though the internal magnet ring may be the same.
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Frequently Asked Questions
Are Galaxy S21 Ultra and OnePlus 12 the same size?
Galaxy S21 Ultra measures 165.1×75.6×8.9mm while OnePlus 12 measures 164.3×75.8×9.2mm. They are different sizes.
Can I use a Galaxy S21 Ultra screen protector on OnePlus 12?
Same screen size (6.82") with minimal width difference — should fit.
What's different between Galaxy S21 Ultra and OnePlus 12 dimensions?
The height differs by 0.8mm, the width by 0.2mm, and thickness by 0.3mm. The camera module layout is also different.
Do I need a new case for OnePlus 12?
Yes, you'll need a new case. The OnePlus 12 has different dimensions than the Galaxy S21 Ultra, so cases are not interchangeable.
Will Galaxy S21 Ultra accessories work with OnePlus 12?
Chargers and cables are compatible since both phones use the same usb-c port. Both support wireless charging, so wireless chargers work with either phone. Cases and screen protectors depend on exact dimensions — check our compatibility results above.
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