Short answer. Yes. When an action is brought against a defendant who ordinarily resides within the Philippines, but who is temporarily out of it, the Rules allow service to be effected outside the country — but only by leave of court. His absence abroad does not put him beyond the reach of your suit.
What the law says
service may, by leave of court, be also effected out of the Philippines
Rule 14, Section 18 — Residents temporarily out of the Philippines. Read the full provision →
The rule fits this exact situation
The provision addresses the defendant caught between two places: someone who ordinarily resides within the Philippines, but who is temporarily out of it — the overseas worker on contract, the employee seconded abroad, the resident on a long trip. For that defendant, the Rules say service may, by leave of court, be also effected out of the Philippines. The suit is filed here, in the Philippine court; only the delivery of the summons crosses the border. So a plaintiff need not wait months or years for the defendant's return before the case can move.
"By leave of court" — ask first
Service abroad under this rule is not something a plaintiff or process server simply goes ahead with. The phrase by leave of court means the court's permission must be obtained before the summons travels: you apply to the court, explain that the defendant ordinarily resides here but is temporarily abroad, and ask that service be effected outside the country in the manner the Rules allow for extraterritorial service. Service made abroad without that prior leave stands on shaky ground, and a defect in service of summons is the kind of flaw that can haunt a judgment years later. Get the order first.
"Also" — an additional mode, not the only one
Note the small word in the text: service may also be effected out of the Philippines. Service abroad is an added option, not a replacement for the ordinary modes. Because this defendant ordinarily resides in the Philippines, his residence here remains a real point of contact with the case — which is precisely why the law treats him differently from a true non-resident. The temporary nature of the absence is the hinge of the rule: what must be shown is that the person you are suing is a Philippine resident who happens to be away, not someone who has left for good.
What to prepare
Before applying for leave, gather what establishes the two facts the rule turns on: proof that the defendant ordinarily resides in the Philippines — a home address, family here, property, a barangay record — and proof that he is temporarily abroad, such as an employment contract overseas or travel records, with his foreign address if you know it. The more precisely you can tell the court where the defendant is and why the absence is temporary, the easier it is to obtain leave and to effect service that will hold up. A lawyer can frame the application and choose the mode of extraterritorial service that fits the facts.