Every new Tesla comes with two ways to get in and drive: your phone, and two key cards. A key fob is the only piece you have to buy separately, and it’s worth knowing what each one actually does before deciding whether you need it.
Phone key: free, but it needs your phone
Your phone is the default key. It connects to the car over Bluetooth, unlocking the doors as you walk up and locking them again as you leave, and — per Tesla North America’s key guide — it needs the Tesla app running in the background with location and Bluetooth permissions turned on. A dead phone battery, a software update that resets those permissions, or a Bluetooth hiccup can all lock you out, which is exactly why Tesla includes a backup with every car.
Key card: the reliable backup
The credit-card-sized key card that ships with every Tesla uses RFID instead of a battery, which makes it the most dependable option when your phone won’t cooperate. Tap it against the door pillar just below the windshield camera to unlock, then set it on the center console and press the brake within 30 seconds to drive. Its one drawback: it can’t lock the car automatically when you walk away, so you either tap it a second time on the pillar or lock up from the app.
Key fob: convenience, for a price
The key fob adds walk-away locking like the phone key, plus physical buttons for the frunk and trunk, so you’re not pulling out your phone every time you need the trunk. It runs on a single coin-cell battery and costs about $175 from the Tesla Shop. It’s most worth it in households with more than one regular driver.
What to actually do
Keep one key card in your wallet as a backup no matter which key you use day to day, and leave the second one at home. One thing no key fixes: if your Tesla’s 12V battery dies, the electronic door handles may not respond even though your key still works. A 12V jump-starter, not a different key, is the real fix for that.
Photo by Mix and Match Studio.