According to the Independent, while the steps will be free after dark, non-residents will need to fork out some cash for their tourist snaps between 9am and 9pm.
The Pantheon has a similar system, charging a €5 ($10) entrance rate for guests from June 2023.
Rome made a whopping €1m ($2m) from the fee within the first month, Britain’s the Times reported.
The Italian capital has long struggled with the effects of overtourism.
Iconic cultural spots such as the Trevi Fountain are increasingly undergoing preservation works to cope with the onslaught of eager travellers.
The monument has been a tourist hotspot for decades and has appeared in several iconic Italian films, attracting as many as 30,000 onlookers a day.
Constructed in 1762, the fountain was commissioned by Pope Clement XII and designed in a Baroque style by Nicola Salvi.
It was traditional for visitors to toss a coin into the water until the practice was banned, with violators facing a €50 ($90) fine.
Wish makers can still honour the custom by throwing their pocket change into a small basin constructed nearby.