Despite still being under contract with the Infiniti Red Bull Racing Formula One team, until officially switching to Porsche from January 1, 2014, Webber tested the Porsche LMP1 on the Autodromo Internacional do Algarve in Portugal.
Joining Porsche's team alongside Timo Bernhard, Romain Dumas and Neel Jani, the Australian F1 driver will make his LMP1 competition debut at the 2014 WEC season opener at Silverstone in April before taking part in the 24 Hours of Le Mans in June.
“This [testing] is a major and important step for us all," Webber said.
"It allows me to integrate with the team quicker, and to contribute to further developing the LMP1 race car.
“We have a long way to go, and it involves a lot of hard work. I have no misconceptions at all.”
Porsche AG research and development head Wolfgang Hatz said the sports car maker always knew returning to top-level endurance racing after 16 years wasn’t going to be easy.
"We are finding new approaches in the development, implementation and application of leading edge technologies,” Hatz said.
“These will lead to improvements of the hybrid technology in our production cars. Ultimately, the customer will benefit the most.”
Porsche’s LMP1 race car uses a high-performance hybrid drivetrain comprising a direct-injection four-cylinder petrol engine, an electric motor and two energy recuperation systems that store energy until retrieved by the driver.
Development of the car is planned to resume from early next year.
Webber officially announced his F1 exit in June, drawing to a close his 12-year career in the sport.