In general terms, it is much more difficult for the trespassing individual to gain compensation after a personal injury than someone on the premises legally.
But, there are a few exceptions to this situation, enabling trespassers to successfully sue the property owner for damages. If the property owner is aware of any serious hazards on their property, they have a duty to address these hazards. Also, if the landowner is aware of trespassing individuals and may begin to expect continued trespassing and still does nothing to address these hazards, they may be held liable.
The chances of a trespasser gaining compensation are slim and depend on many factors. These factors include the likelihood of the trespasser coming onto the property, the severity of the injury, and the location of the property. You should consult an experienced attorney to determine whether you have a valid premises liability claim.