A Coastguard spokeswoman said they were hoping to get in contact with the parents of the two boys.
She said: "We would like to hear from the parents to confirm that the children are, in fact, safe."
It is understood that the boys were reported missing at midday but the parents had not been in contact with the emergency services since about 1pm.
More top news
Their twisted romance revolved around fictional Facebook characters, and the 8-year-old girl was seen as a threat.
Pebble's new Time smartwatch has become the most funded project ever on crowd-funding site Kickstarter after raising more than £10 million.
A mother who revelled in the attention having a poorly child brought has been convicted of poisoning her son to death.