The timeline to join Amazon Brand Registry through trademark registration depends on how quickly the trademark application can be filed and a serial number issued.
Once a complete application is submitted to the IP office, the serial number is typically assigned and recorded in the public database within a few business days. You can then submit that number to Amazon Brand Registry. The full registration process takes several months to over a year depending on the jurisdiction, but Brand Registry does not require it to be complete.
Trama can help you register a trademark for Amazon Brand Registry; free initial check available.