The company said the interest would be acquired from Oil Search and ExxonMobil.
PPL 402 is located about 40 kilometres northwest of the Hides gas field and production facilities in Hela.
It is within the highly prospective thrust and fold belt trend.
The licence covers an area of 510 kilometre- square.
The farm-in results in Santos’ participation in the recently spudded Muruk 1 exploration well.
The Muruk 1 well is targeting the Toro Formation, which is gas-bearing in the nearby Hides and Juha fields. It is expected to have a mean gas resource of around 2 tcf (trillion cubic feet) at a proposed depth of approximately 3,450 metres.
Santos managing director and chief executive officer Kevin Gallagher said Santos had a long and successful working relationship with Oil Search and ExxonMobil.