Spalding Police want to return these two bikes to their rightful owners.
The bikes were hurled into Vernatts Drain, near Two Plank Lane, in Spalding at about 3pm on Easter Monday (March 28).
An off-duty officer saw it happening and the youths were arrested on suspicion of theft and later bailed.
Police said: “One bike is a blue Apollo Envy ladies’ mountain bike and the other is a silver gents’ mountain bike with no names or maker.
“If you believe either of the bikes belongs to you, or you have any further information which may assist, please contact PC Alastair Pullen at Spalding Police Station by calling 101, or visiting the station.”
Incident number is 197 of March 28.