Where is the fuel filter situated on a 2002 mazda astina wagon sp20.

I can't answer your question but I thought I would mention not all cars are fitted with a replaceable fuel filter - some are fitted with a lifetime filter.

I suggest you check the online filter catalogues of the various filter manufacturers. If you don't find a listing for your model it is probably because it has a lifetime filter.

If there is an application for your model it will be located where it is convenient for routine replacement - underneath at the rear or in the engine compartment are the two most common places, If in doubt following the fuel line(s) should provide the answer...