They were arrested by the Malaysia Maritime Enforcement Agency (MMEA) after the Eastern Sabah Security Command (Esscom) spotted a few boats entering the border.
"Acting on the information from Esscom, we found the three boats in a restricted curfew area and found 21 Indonesian and one Malaysian crewmen aged between 20 and 30.
"All detainees have been brought to Semporna for further investigations under the Police Act.
"They will be facing a fine of RM500 or six months' jail upon conviction," said Maritime District Enforcement Chief, Captain Anor Jaafar.
Anor urged the maritime community in the East Coast, especially local fishermen, to adhere to the curfew orders.
"They must obtain exemption permits from the police with reasonable grounds or emergency to travel during curfew hours," he said.
Anor also hoped the public will provide information on maritime crimes at MERS 999 or Tawau MMEA Hotline at 089 752115.