A city public works employee doing a routine morning inspection of parks and recreation facilities Monday spotted the device and called police, The (St. John's) Telegram reported.
Parents and children arriving for tennis lessons were ordered out of the park, the report said.
The Royal Newfoundland Constabulary responded and requested the city close all of its facilities as a precaution, the newspaper said.
A robot was used to analyze and retrieve the bomb, which was wrapped in black tape and about the size of a beer bottle, the Canadian Broadcasting Corp. reported.
The city ordered an afternoon inspection of all of its properties but nothing else was found. All parks and recreational facilities reopened Tuesday, the reports said.