Does Digital Key 3.0 mean my key fobs are also relay resistant ?

Even if a vehicle supports smartphone Digital Key 3.0 (which requires UWB signalling), it will still normally be supplied with one or more physical key fobs. Manufacturers do not generally disclose the detailed security characteristics of these fobs, and in practice customers are rarely told which anti-relay protections are present. In most modern implementations, the presence of UWB hardware for the phone key also means that UWB is used by the physical key fob, but this is not guaranteed. In rare cases or specific regional or fleet variants, a model may support Digital Key 3.0 while the supplied physical key fob lacks either UWB or additional mitigations such as motion-sensor sleep, or both. As a result, owners should not assume that Digital Key 3.0 support automatically implies equivalent protection for the physical key fob, and those concerned about relay theft may choose to treat a smartphone using Digital Key 3.0 as the primary access method and store physical key fobs in good faraday pouches out of sight inside their house. Putting the faraday pouches inside a metal tin with a tight-fitting lid adds an extra layer of protection (don’t use tin foil – the seal it creates is unreliable). 

ADAC’s keyless-theft testing is performed using the physical key fob rather than smartphone Digital Keys. Where ADAC reports a vehicle as “better secured with UWB” (“besser gesichert mit UWB”), this indicates that the tested physical key fob itself used UWB-based proximity protection. If a vehicle reported in this way also supports Digital Key 3.0, it is therefore reasonable to conclude that the supplied physical key fobs use UWB, in the car tested by ADAC (in Germany). ADACs results are a very useful guide, but not a total guarantee for UK-spec cars, as features can vary by market and model year.