De or het schoolwandeling?

The correct Dutch article is:

de schoolwandeling

Rule Words ending in -ing: almost always de. See the rule

How to use schoolwandeling

the schoolwandelingde schoolwandeling
this schoolwandelingdeze schoolwandeling
that schoolwandelingdie schoolwandeling
our schoolwandelingonze schoolwandeling
your schoolwandelingjouw schoolwandeling
every schoolwandelingelke schoolwandeling
which schoolwandeling?welke schoolwandeling?
a big schoolwandeling / the big schoolwandelingeen grote schoolwandeling, de grote schoolwandeling