Six people were killed and 33 injured when the IRA detonated the devices on June 12, 1973. The commemoration will include the unveiling of a permanent memorial to those who died.
Alderman Yvonne Boyle, who will accompany party colleagues Councillor Richard Stewart and Councillor Amy Mairs to the event on Monday, said her thoughts were with all those affected.
“As this anniversary approaches, my thoughts and sympathies are with the friends and families of those who were killed in this terrible attack, as well as those who were injured in the attack,” said Alderman Boyle.
“Even 50 years later, the shadow of the bombings still hangs heavy over Coleraine. The dark day lives long in the memory of all those who lived here at the time in particular, with lives lost and others changed forever. All those affected have shown a bravery which can only be commended.
“It is important we remember all lives lost to terrorism, both here and further afield, and stand united in opposition to it. That is especially vital when a minority remains today who would drag us back to our troubled past.”