Check if list contains item from other list in EntityFramework

I'll suggest:

var searchIds = new List<int>{1,2,3,4,5};
var result = persons.Where(p => p.Locations.Any(l => searchIds.Contains(l.Id)));

Contains will be translated to IN statement.

Keep in mind that the id list goes into the sql statement. If your id list is huge then you'll end up having a huge query.

Try switching to joins instead of doing a massive data include:

var searchIds = new List<int>{1,2,3,4,5};
var results = (from p in persons
               join l in Location on p.PersonId equals l.PersonId
               where searchIds.Contains(l.Id)
               select p).Distinct().ToList();

Obviously fix this line to match your classes and/or join property.

join l in Location on p.PersonId equals l.PersonId

I would expect that to generate a more friendly execution plan.