| Hardware and OS | Samsung Galaxy S21 Plus 5G | Oppo A3s |
| Operating system | Android 11, One UI 3.1 | Android 8.1 (Oreo); ColorOS 5.1 |
| Processor | Octa-core (1x2.9 GHz Cortex-X1 & 3x2.80 GHz Cortex-A78 & 4x2.2 GHz Cortex-A55) - International / Octa-core (1x2.84 GHz Kryo 680 & 3x2.42 GHz Kryo 680 & 4x1.80 GHz Kryo 680 - USA/China | Octa-core 1.8 GHz Cortex-A53 |
| Chipset | | Qualcomm SDM450 Snapdragon 450 (14 nm) |
| GPU | Mali-G78 MP14 - International / Adreno 660 - USA/China | Adreno 506 |
| RAM | 8 GB | |
| Internal memory | | 16 GB, 2 GB RAM |
| Internal Storage | 128 GB, 256 GB | |
| External memory | | microSD, up to 256 GB (dedicated slot) |
| Memory Card Slot | No | |
| User Interface | Yes | |
| Display | Samsung Galaxy S21 Plus 5G | Oppo A3s |
| Type | Dynamic AMOLED 2X | IPS LCD |
| Size | 6.7 inches | 6.2" inc |
| Resolution | 1080 x 2400 pixels | 720 x 1520 px |
| Touchscreen | Yes | capacitive touchscreen |
| Screen-to-Body Ratio | | 81.2% |
| Display area | | 95.9 cm2 |
| Display aspect ratio | | 19:9 (height:width) |
| Pixel Density | 394 PPI | 271 PPI |
| Protection | Corning Gorilla Glass Victus | |
| Colors | 16M | 16M |
| Features | Always-on display, | |
| Connectivity | Samsung Galaxy S21 Plus 5G | Oppo A3s |
| 2G Network | | GSM 850 / 900 / 1800 / 1900 - SIM 1 & SIM 2 |
| 3G Network | | HSDPA 850 / 900 / 2100 |
| 5G Network | SA/NSA/Sub6/mmWave | |
| 4G Network | 1, 2, 3, 4, 5, 7, 8, 12, 13, 14, 18, 19, 20, 25, 26, 28, 30, 38, 39, 40, 41, 46, 48, 66, 71 - SM-G996U1 | LTE |
| Wi-Fi | Wi-Fi 802.11 a/b/g/n/ac/6, dual-band, Wi-Fi Direct, hotspot | Wi-Fi 802.11 b/g/n, WiFi Direct, hotspot |
| Network | | GSM / HSPA / LTE |
| NFC | Yes | |
| SIM card | | Dual SIM (Nano-SIM, dual stand-by) |
| Bluetooth | | 4.2, A2DP, LE |
| Edge | | Yes |
| SIM | Nano SIM | |
| GPRS | | Yes |
| Dual SIM | Single SIM (Nano-SIM and/or eSIM) or Hybrid Dual SIM (Nano-SIM, dual stand-by) | |
| GPS | Yes, with A-GPS, GLONASS, BDS, GALILEO | Yes, with A-GPS |
| Wireless Charging | Yes | |
| Speed | HSPA 42.2/5.76 Mbps, LTE-A (CA), 5G | HSPA 42.2/5.76 Mbps, LTE-A (2CA) Cat6 300/50 Mbps |
| USB | USB Type-C 3.2, USB On-The-Go | microUSB 2.0, USB On-The-Go |
| Camera | Samsung Galaxy S21 Plus 5G | Oppo A3s |
| Main camera | 12 MP (wide), 64 MP (periscope telephoto) 1.1x optical zoom, 3x hybrid zoom, 12 MP (ultrawide) Super Steady video. | 13 MP, Dual |
| Image | 4320p | |
| Specs | | 13 MP, f/2.2, AF
-2 MP, f/2.4, depth sensor |
| Features | LED flash, auto-HDR, panorama | LED flash, HDR, panorama |
| Video | | 1080p@30fps |
| Selfie camera | 10 MP (wide) | 8 MP, Single |
| Multimedia | Samsung Galaxy S21 Plus 5G | Oppo A3s |
| Loudspeaker | Yes | |
| Handsfree | Yes | |
| Video Playback | Yes | |
| 3.5 mm Jack | No | Yes |
| Video Out | Yes | |
| Radio | FM radio (Snapdragon model only; market/operator dependent) | FM radio |
| Ring Tones | Yes | |
| Design | Samsung Galaxy S21 Plus 5G | Oppo A3s |
| Colors | | Red, Dark Purple |
| Dimensions | 161.5 x 75.6 x 7.8 mm | 156.2 x 75.6 x 8.2 mm |
| Weight | 200 g | 168 g |
| Waterproof | IP68 dust/water resistant (up to 1.5m for 30 mins) | |
| Battery | Samsung Galaxy S21 Plus 5G | Oppo A3s |
| Battery capacity | | 4230 mAh, Non-removable Li-Ion |
| Capacity | Li-Po 4800 mAh, Fast charging 25W, USB Power Delivery 3.0, Fast Qi/PMA wireless charging 15W, Reverse wireless charging 4.5W. | |
| Placement | Non-removable | |
| Other | Samsung Galaxy S21 Plus 5G | Oppo A3s |
| Release date | | 2018, July |
| Sensors | | Accelerometer, proximity, compass |
