Two men – one carrying a knife and the other an extendable baton – walked into a petrol station on the Crumlin Road just before 6.45 pm.
They threatened staff before fleeing with cash from the till towards Cliftonpark Avenue.
Police describe one of them as wearing a yellow coloured hooded top and grey track bottoms while the other was wearing a black jacket and blue track bottoms.
Three hours later, a man robbed a petrol station on the Shankill Road armed with an iron bar.
He fled with cash after threatening staff towards Crosby Street where he met an accomplice.
Police describe the armed man as around 5 ft 10 inches tall, nd in his late teens or early 20s.
He was wearing a white and grey hooded top and blue track bottoms.
Police are appealing for any witnesses to either of the robberies to come forward.