If you travel abroad primarily for vacation but attend some business or professional seminar, you may not deduct any portion of the trip as a business expense. You may, however, deduct the cost of the seminar (registration fees and other related expenses) as a business expense.
Your professional association sponsors a two-week trip abroad. It holds two three-hour seminars during the trip and awards a Certificate in Continuing Education to those who attend the seminars. The entire cost of the trip is a non-deductible personal expense, as it is viewed as primarily for vacation. However, the registration fees for the seminars are deductible.
If you are in a combined (federal, self-employment, and state) tax bracket of 30%, you could reduce your taxes up to $300 for every $1,000 of income reduction by deducting the seminar costs if your trip is primarily for vacation.