Steve Davies and Howard Jeffrey, who work in Porth and David Boyce, from Mountain Ash, will fly to the American city on Sunday for a five day trip.
During their stay, they will take part in memorial services to mark the anniversary of the attacks on the World Trade Centre and the Pentagon, when hijacked passenger planes were deliberately flown into the buildings.
The part-time volunteer police officers, will also carry out a tour of duty with the New York Police Department and will meet the city's mayor.
Steve Davies, 22, who works for a parcel delivery company as well as serving as a special constable, said he was looking forward to the experience.
"We are going out there on Sunday to remember those who were tragically killed," he said.
"We are going to show our solidarity and support for the people in the US.
"New York Police Department lost 23 officers and the New York Port Authority lost 37 officers in the attacks," said Mr Davies.
While in New York, the three officers will go to two memorial services.
"On the 10 September, we are attending a service with Tony Blair and Jack Straw to remember the British victims," said Mr Davies.
"On 11 September, we will go to the official memorial service."
Ground Zero visit
The special constables will join hundreds of officers from across the UK who are travelling to New York.
"We will visit Ground Zero," he added.
"I am really looking forward to that - it will be very interesting to see how different it is."
John Jones, divisional commander for Rhondda Cynon Taff said the officers were representing the whole of South Wales Police.
He said: "I have no doubt that they will prove ideal ambassadors whilst in America.
"Although I am not able to attend myself, I would like to convey my deepest sympathies to our counterparts in America and let them know we are thinking of them at this emotional time."