Border Tunnel Prevention Act - Amends the federal criminal code to prohibit the construction or financing of an unauthorized tunnel or subterranean passage that crosses the international border between the United States and another country. Imposes a 20-year prison term for such offense. Doubles penalties for persons who use such a tunnel or passage to smuggle an alien, illegal goods, controlled substances, weapons of mass destruction, or members of a terrorist organization

Imposes a 10-year prison term on any person who knows of or recklessly disregards the construction or use of an unauthorized tunnel or passage on land that such person owns or controls.

Subjects to forfeiture any property involved in, or traceable to, the construction or financing of an unauthorized tunnel or passage.

Directs the U.S. Sentencing Commission to promulgate or amend sentencing guidelines to provide for increased penalties for persons convicted of criminal offenses related to the construction or financing of an unauthorized tunnel or passage.