It's the ultimate case of the one that got away.

Two teenage boys on Friday handed police almost $100,000 cash they found earlier this month during a fishing trip at Tuntable Creek, north of Lismore on the NSW north coast.

They recently told a carer about their ultimate catch and after seeking legal advice, decided to alert police.

Officers searched the area where the boys say they found the cash but failed to find anything to help inquiries.

Police are now looking for the lawful owner of the money.

Anyone with information is urged to contact Lismore police station.