It depends on your budget and the number of people but I would look at Samal Island for a conference and seminar location in the Davao area.
Samal Island: is less than one hour from Davao International Airport; weather is predictable year round (no typhoons); a number of beach resorts have meeting, conference and seminar location facilities.
At the top end of the budget scale you could try the Pearl Farm Beach Resort
, one of the World's best beach resort locations on the recently voted Best Vacation Island of Samal
If you are looking for a more economic but well catered meeting, conference and seminar location then check out the Punta Del Sol Beach Resort
on Samal Island = relaxing and tranquil with accommodations of all levels, including camping - always a good team building exercise.
If you would alternatively consider a city conference and seminar location then there is always the Marco Polo Hotel in downtown Davao City - pricey but with a view over the entire city and they can arrange team building away-trips to Samal Island.