I understand that GA won't provide legal advice and all manner of
disclaimers apply.  Nevertheless, please help where you can:

Is it legal for a tourist to carry a knife in the Philippines and if
so, what are the limitations (size, etc.)

I am considering trekking around far from 'civilisation' and want to
carry a 7" fixed blade in my pack/ on my belt and a 3.5" folder in my
pocket.  I will be mostly in the provinces, but may pass through Metro
Manila.

Hi! Thanks for the question.

It is very clear that carrying a knife outside of one's residence is
unlawful for foreigners or local residents alike unless you use it to
earn a living (ex. a farm worker).

"'3. It is unlawful to carry outside of one's residence any bladed,
pointed or blunt weapon such as  "knife", "spear", "pana", "dagger",
"bolo", "barong", "kris", or "chako", except where such articles are
being used as necessary tools or implements to earn a livelihood or in
pursuit of a lawful activity. Any person found guilty thereof shall
suffer the penalty of imprisonment of not less than one month nor more
than one year or a fine of not less than Two Hundred Pesos nor more
than Two Thousand Pesos, or both such imprisonment and fine as the
Court may direct.'."

"Any law or ordinance which is inconsistent herewith is hereby repealed."

"BATAS PAMBANSA BILANG 6"
http://www.chanrobles.com/bataspambansabilang6.htm

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Searched for documents at the Chan Robles Law website
         
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Regards,                 
Easterangel-ga                 
Google Answers Researcher

Thank you for your 5* answer.  I'll be posting an identical question
on Thailand that you may also like to have a crack at.

Thanks for the kind words, the 5 stars and for the tip! I tried to
find information about Thailand but have been unsuccessful so far.
Maybe another researcher will find the right information for you.

Thanks again.