Masked robbers threatened a group of teenagers with a knife before making off with their mobile phones.
Three 16-year-old boys were waiting for a taxi in Birstall when they were approached by two men in their 20s.
One man asked for a cigarette and then threatened the boys with a knife and demanded their phones.
The second man also produced a knife and threatened the teens.
All three of their phones were stolen in the robbery, which took place between 1.30am and 1.40am on Sunday, July 3.
One of the suspects was white, about 6ft tall and muscular with a round stomach. He was wearing a grey hooded top with the hood up, a black scarf covering his face and dark coloured jogging bottoms.
The other was white, also about 6ft tall, thin and wearing a dark hooded top with the hood up, a black scarf covering his face and black shorts.
DC Andy Clayton of Huddersfield CID, said: “Enquiries are ongoing into this robbery which was clearly a very frightening experience for these three teenagers.
“I would ask anyone who has information or who perhaps identify these suspects to contact the Kirklees Reactive CID on 101.
“Information can also be given to the independent Crimestoppers charity on 0800 555 111.”