Short answer. Yes. Improper venue is an affirmative defence that must be raised in the answer, and Rule 8, Section 12 is blunt about the cost of silence: failure to raise the affirmative defenses at the earliest opportunity shall constitute a waiver thereof. Once waived, the case stays where it was filed.
What the law says
Failure to raise the affirmative defenses at the earliest opportunity shall constitute a waiver thereof.
Rule 8, Section 12 — Affirmative defenses. Read the full provision →
What the law says
That venue is improperly laid;
Rule 8, Section 12 — Affirmative defenses. Read the full provision →
Venue objections belong in the answer
Rule 8, Section 12 directs that a defendant shall raise his or her affirmative defenses in his or her answer, and its list of grounds includes, in terms, That venue is improperly laid. Venue sits alongside lack of jurisdiction over the person, lack of legal capacity to sue, failure to state a cause of action, and non-compliance with a condition precedent. The design pushes all of these threshold objections to the front of the case: they are pleaded at the start, in the responsive pleading, or they are not pleaded at all.
The waiver is written into the rule
The section answers your question in one sentence: Failure to raise the affirmative defenses at the earliest opportunity shall constitute a waiver thereof. Venue is a rule of convenience about where a case is heard, not a limit on the court's power to hear it, which is why the law is content to let the objection die with silence. A defendant who answers on the merits without protesting the venue has accepted the forum, and the case proceeds there to judgment. There is no reviving the objection later in the trial court once the waiver has attached.
What happens when the defence is raised in time
Raising the defence promptly triggers the section's timetable rather than a long detour: The court shall motu proprio resolve the above affirmative defenses within thirty calendar days from the filing of the answer. No motion or hearing needs to be demanded for the listed grounds — the court is directed to resolve them on its own within the period. The scheme rewards the defendant who front-loads the objection with an early answer on it, and it deprives threshold defences of their old capacity to stall a case for months.
If the defence is denied
A denial is not immediately reviewable. The section forecloses the usual interlocutory routes: affirmative defences, if denied, shall not be the subject of a motion for reconsideration or petition for certiorari, prohibition or mandamus, but may be among the matters to be raised on appeal after a judgment on the merits. So a defendant whose venue objection is rejected litigates the case where it stands, preserves the point, and re-argues it on appeal if the judgment goes against them. What cannot be done is the opposite order — stay quiet in the answer and hope to raise venue for the first time later.