The victim, a 15-year-old, was with friends when he was approached by three other youths – who are known to police – in Bell Farm Road around 4pm on Monday 28 October.
They continued into an alleyway near Tesco, where the victim was pushed to the floor and forced to hand over his footwear.
Police responded and all three suspects – local boys aged 17, 15 and 14 – were arrested within 24 hours, on suspicion of robbery. All three have been interviewed and released on conditional bail until 26 November, pending further enquiries.
The victim was left shaken but not hurt, and his trainers were later recovered and returned to him.
Inspector Jon Gross said: “Officers have worked swiftly to identify the suspects involved and take enforcement action. Tackling this type of incident is a priority for Sussex Police and I would caution anyone against getting involved in serious offences such as this.
“There is an excellent working relationship within the town between local officers and community leaders, and on all sides a commitment to tackling perpetrators of public place antisocial behaviour and violence. Crimes of this nature will not be tolerated.”
Anyone who witnessed what happened is asked to report it online or call 101, quoting serial 915 of 28/10.