Dublin Fire Brigade said it has received 244 fire call-outs and 401 ambulance callouts this Halloween night.
The number of calls this year is higher than on 31 October 2024, it said.
It said in the wider Eastern area, firefighters have received 140 fire calls.
Halloween is the busiest night of the year for emergency services due to illegal bonfires and firework displays.
Navan's Fire Station Officer Declan Corbett said his station has received eight calls, mostly bonfires.
He said firefighters are concerned about "what's actually in" these bonfires.
Gardaí have advised people to be safe and sensible as festivities continue.
Meanwhile, Chief Fire Officer at Dublin Fire Brigade Greg O'Dwyer said the number of calls the fire service will receive on Halloween will more than likely be triple the number it would normally receive on a busy Saturday night.
"Last year we saw Halloween-related calls reaching almost 500 calls for the 24-hour period between 4.30pm on Halloween evening up to the next day," he told RTÉ's Drivetime.
He said extra "call takers" will be deployed, all of Dublin Fire Brigade's resources will be fully staffed, and a system put in place to assess bonfires and which ones to prioritise, dealing with those affecting "life or property first".
