She clutched her newborn baby boy tightly to her chest during the appearance in Sydney.
Phoebe dressed casually to run errands, wearing a loose fitting floral frock paired with dark glasses.
Wearing her blonde hair tied back in a simple ponytail, she clutched a straw handbag.
Phoebe also still appeared to be wearing her wedding ring on her left hand.
Following the reported marriage split between Phoebe and Sam, the WAG has received overwhelming support on social media – with Lara Bingle even reaching out with a message.
Lara’s post - alongside the last photo Phoebe shared before Christmas - came directly underneath that of a fan who commented: “My heart is breaking for you”.
Sam is thought to have ended the couple’s relationship just before Christmas and Phoebe was not seen at the Burgess family Christmas dinner held at Watson’s Bay.
Phoebe is said to have spent Christmas with her parents in their Bowral home.
A source close to the pair told The Daily Telegraph that “things have been bad for a while”.
“They tried to keep it together but it all went to s**t, that's the honest truth. It is pretty messy,” the source said.