There's been a rise in the number of prisoners at Lincoln caught with smuggled mobile phones or sim cards.
They can be used to order drugs and co ordinate criminal activity inside and outside jail.
Last year 47 were confiscated, compared to just 1 back in 2013.
There's been increases across the country, including at Morton Hall in Swinderby.
The prison service argue they're finding more because they've increased security.