It's not clear where he made the call from. It's possible he could have been at the beach and not mentioned it but also possible if he did go to the beach it was much later than just after midnight. The timeline is he left CM around 11pm and then:
"Theo's phone was last recorded shortly after midnight being somewhere east of the CBD of Byron Bay, in a north-east direction up towards the lighthouse.
"Our last recorded phone records that the phone was used in and around this area," Tweed Byron Police District Chief Inspector Matt Kehoe said.
Timeline of a mystery: Theo's last known movements