The ship will be in the harbour until Monday, September 30 and during the five-day visit, it will play host to the public highlighting the diverse range of job opportunities a career in the armed forces can offer.
The visit has been organised to support the Belfast Armed Forces Career Exhibition.
The exhibition takes place at Kinnegar Logistics Base, Holywood this Saturday and Sunday between 10am and 4pm.
The event will include a forum for students interested in a career in engineering.
Weapon Engineer Officer Lieutenant Commander John Brennan said: "The Royal Navy offers fantastic career opportunities and we are looking forward to showing potential recruits the impressive capabilities of a modern warship, whilst being able to meet the personnel who serve in her."
Sarah West commanding officer of HMS Portland added: "I am delighted that HMS Portland is able to visit Belfast.
"The city is a popular destination with the Royal Navy due to the hospitality of the people and the range of activities available.
"My ship's company are excited about the visit."
West was the Royal Navy's first ever female commanding officer appointment to a frontline warship in its 500 year history.
The ship's sports teams will also be in action against local teams throughout the visit with a busy fixture list that includes football, golf, netball and both men's and ladies' rugby.
HMS Portland has recently completed a 12-month upgrade to her weapons and sensors making her the most modern and capable frigate within the Royal Navy.