One of the vehicles is blue, the other green.
The theft is thought to have occured between 2am and 3am.
A police spokesman said: “Please be aware, we are experiencing numerous thefts of Defenders in our region.
“ If you own one, please ensure it has adequate security overnight.
“A hand brake/gear lever lock is recommended.”
If you have any information on the Otby theft, call police on 101 and quote 17000043178.