William Hill already runs two sportsbooks in the Garden State, at the Ocean Resort Casino in Atlantic City and at Monmouth Park Racetrack.
FanDuel, which operates at Meadowlands Racetrack, launched its sportsbooks after a five-day test period was permitted by the New Jersey Division of Gaming Enforcement.
The approvals take the mobile sports betting operators in the state up to five.
Previously approved brands include Borgata, Draft Kings (which partners with Resorts casino) and PlaySugarHouse.com
Operators are keen to be granted approval for mobile sports betting before the start of the NFL season on Friday, with six of Atlantic City’s nine casinos offering land-based sports betting, as well as two racetracks.
Court proceedings are currently ongoing at the former Garden State Park racetrack, to see if the racetrack is eligible to have sports betting.
Sports betting revenue in the state for the first six weeks amounted to $57m after the activity was legalised in mid June.
