The timeframe is within 15 days after receipt of the currency or monetary instruments.

A person (department) must file Form 4790 if that person (department) physically transports, mails, or ships, or causes to be physically transported, mailed, shipped or received currency or other monetary instruments in an aggregate amount exceeding $10,000.00 on any one occasion from the United States to any place outside the United States, or into the United States from any place outside the United States. Monetary instruments are defined, in part, as the coin or currency of the United States or any other country, travelers’ checks, and money orders. Bank drafts payable to persons or companies domiciled outside the United States would be included.