Tesla have historically provided all cars with premium connectivity without them realising, but from 2019 they have introduced this as a subscription model for some owners. The subscription provides the capability to access some of the car’s features over cellular/mobile networks.
Irrespective of premium connectivity all Teslas come with Standard Connectivity. This allows the cars to receive limited software updates over-the-air (although the general advice is to connect to your home wifi for the fastest updates). Navigation functionality is the same as with premium connectivity except the lack of both satellite imagery and traffic visualisations.
Features such as Bluetooth connectivity to your phone, Radio (not internet radio) and MP3 music are also available as these are not related to connectivity. You also have remote app connectivity to the car. Other than the navigation visualisations, the main functionality that is lost relates to media services such as streaming and Caraoke.
If you opt for premium connectivity you will get Satellite imagery on the map, live traffic visualisation, and media services such as Spotify or Deezer depending on region and streaming radio via services like TuneIn.
For cars that have the necessary hardware (ie M3 and MS and MX with MCU2), services like Caraoke are available.
Essentially, any service that is not mandatory for the core driving features of the car are only accessible over the air if premium connectivity is selected, or if the car is connected to wifi.
Tesla state that all except Live traffic and Satellite-View Maps are available via WiFi including mobile phone hotspots.
Some users report even these sat nav related features are also available via wifi hot spots on the move. The downside to this approach however is the car will drop the wifi connection as soon as the car is put into D and you will need to manually reconnect. Its pretty clunky but if all you want is some services while charging, its an option.
New cars come with a free trial period, the length of which varies depending ont he model. After that its about $10/£10/10Euro as a guide.
The dates Tesla have used have not been consistently applied to the contracts and web site documentation and some buyers feel Tesla have retrospectively applied the rules requiring them to now pay. Some countries such as Australia and New Zealand have been successful in getting to make changes although the numbers of buyers this affects is relatively small.