It shut during the coronavirus pandemic to restrict access for visitors, preventing the virus from spreading.
Since then, all visitors and patients have had to use the Gwyneth Huelin Wing to access the hospital.
Patrick Armstrong, the island's Medical Director says the decision to re-open the entrance on The Parade came after reviewing recent Covid-19 and flu figures:
"We are pleased to be able to open the Parade entrance once again; it will be welcome news for patients. But we must not be complacent. Islanders who come to the hospital for any reason have a critical role to play in ensuring that a healthy environment is maintained.
"We will continue to remind everyone that they must continue to wear a mask whenever they visit the Hospital, no matter what ward or department they are visiting. Wearing masks continues to protect vulnerable patients and staff who work in the Hospital."
He added that officials will continue to closely monitor Covid-19 case numbers and adjust restrictions at the hospital if needed.
Visitors are still being asked to stay away if they feel unwell and to take a lateral flow test before arriving at the hospital.