No built-in Wi-Fi. The launch-model "Phat" DS (2004) requires external hardware for online:
| Model | Wi-Fi | Security Support |
|---|---|---|
| DS Lite | ✅ | WEP only |
| DSi / DSi XL | ✅ | WPA/WPA2 (AES/TKIP) |
| 3DS / 2DS family | ✅ | WPA2/WPA3, 802.11n (New 3DS) |
Nintendo Wi-Fi Connection service shut down May 20, 2014 — all official online play dead. Homebrew (Wiimmfi, AltWFC) restores some titles.