Samsung Galaxy S21 Ultra vs Samsung Galaxy S25 Ultra
If you'd rather pay up front, the S21 Ultra 5G is the cheaper buy at £210 SIM-free.
10 reviews 4.4
12 reviews
Prices updated 11 July 2026
Samsung Galaxy S21 Ultra
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Samsung Galaxy S25 Ultra
|
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|---|---|---|
| Expert Rating | 4.4 10 reviews |
4.4 12 reviews |
| Screen | 6.8" | 6.8" |
| Display | Dynamic AMOLED 2X capacitive touchscreen | Dynamic LTPO AMOLED 2X |
| Resolution | 1440 x 3200 | 1440 x 3120 |
| Pixels Per Inch | 516 | 505 |
| Rear Camera | 108 Megapixels | 200 Megapixels |
| Front Camera | 40 Megapixels | 12 Megapixels |
| Chipset | Exynos 2100 | Qualcomm SM8750-AB Snapdragon 8 Elite (3 nm) |
| Battery | 5,000 mAh | 5,000 mAh |
| Storage | 128GB, 256GB, 512GB | 256GB, 512GB, 1TB |
| OS | Android 11 | Android 15 |
| SIM Type | Nano SIM | nano-SIM and e-SIM |
| Connectivity | Up to 5G | Up to 5G |
| Wi-Fi | 802.11 a/b/g/n/ac/6 | 802.11 a/b/g/n/ac/6e/7 |
| Bluetooth | 5.1 with A2DP, LE | 5.3, A2DP, LE |
| Dimensions | 165.1 x 75.6 x 8.9 mm | 162.8 x 77.6 x 8.2 mm |
| Weight | 228 grams | 219 grams |
| Water Resistance | IP68 - Dust and water resistant over 1.5 meter and 30 minutes | IP68 - Dust and water resistant over 1.5 meter and 30 minutes |
| Contracts | - |
£33.79/mo
£29.00 upfront |
| SIM-free | £209.99 | £569.99 |
| Prices updated 11 July 2026 | ||
| Deals | Deals | |
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Frequently Asked Questions
Which has the better screen, the Samsung Galaxy S21 Ultra or Samsung Galaxy S25 Ultra?
Both phones have a similar screen size at around 6.8", the Samsung Galaxy S21 Ultra has the sharper display at 516 pixels per inch versus 505, and the Samsung Galaxy S21 Ultra uses a Dynamic AMOLED 2X capacitive touchscreen panel while the Samsung Galaxy S25 Ultra has a Dynamic LTPO AMOLED 2X.
Which has the better camera, the Samsung Galaxy S21 Ultra or Samsung Galaxy S25 Ultra?
The Samsung Galaxy S21 Ultra features a 108 Megapixels rear camera, while the Samsung Galaxy S25 Ultra has a 200 Megapixels rear camera. Both devices also have front-facing cameras for selfies and video calls.
Which is cheaper to buy SIM-free, the Samsung Galaxy S21 Ultra or Samsung Galaxy S25 Ultra?
The Samsung Galaxy S21 Ultra is cheaper SIM-free, starting from £209.99.
What storage options are available for the Samsung Galaxy S21 Ultra and Samsung Galaxy S25 Ultra?
The Samsung Galaxy S21 Ultra is available in 128GB, 256GB, 512GB, while the Samsung Galaxy S25 Ultra comes in 256GB, 512GB, 1TB.
What processors do the Samsung Galaxy S21 Ultra and Samsung Galaxy S25 Ultra use?
The Samsung Galaxy S21 Ultra is powered by the Exynos 2100, while the Samsung Galaxy S25 Ultra uses the Qualcomm SM8750-AB Snapdragon 8 Elite (3 nm).
Which is easier to carry and hold, the Samsung Galaxy S21 Ultra or Samsung Galaxy S25 Ultra?
It's a trade-off: the Samsung Galaxy S25 Ultra is lighter but the Samsung Galaxy S21 Ultra is more compact. It's 9g lighter at 219 grams, though the Samsung Galaxy S21 Ultra is actually the more compact phone at 165.1 x 75.6 x 8.9 mm, the Samsung Galaxy S25 Ultra is slimmer at 8.2mm thick.
Which is more water resistant, the Samsung Galaxy S21 Ultra or Samsung Galaxy S25 Ultra?
Both phones share the same water resistance rating of IP68 - Dust and water resistant over 1.5 meter and 30 minutes.
What operating system do the Samsung Galaxy S21 Ultra and Samsung Galaxy S25 Ultra run?
The Samsung Galaxy S21 Ultra runs Android 11 and the Samsung Galaxy S25 Ultra runs Android 15. This is one of the biggest factors when choosing between the two, as each ecosystem has its own apps, services and features.