Getting reservations in advance of your departure for performances in Europe can take some homework.

First, contact the national tourism office of the country you plan to visit to determine what the procedures are for individual theaters and concert halls. Every West European nation has a tourist office in New York. These offices usually can provide schedules at least a few weeks in advance.

Among the other possibilities:

Write the theater directly. The national tourism office or a guidebook can provide the address.

Write or phone the concierge desk of the hotel where you plan to stay. Or visit the desk as soon as you check in. Tickets are a standard service of European concierges, who should be tipped. This may be the surest way to get good tickets, since you have a knowledgeable agent working for you at the scene.

Contact a New York-based ticket agency. The following provide a ticket reservation service to selected performing arts companies. For theater, musical comedy, opera, symphony concerts and ballet in London and Dublin, Keith Prowse (1-800-223-4446) or Edwards & Edwards (1-800-223-6108). For the Vienna State Opera, the Spanish Riding School and the Vienna Boys Choir in Vienna, Dial Austria (1-800-221-4980).

Check with your airline. British Airways provides a service for its transatlantic passengers to London performances of the English National Opera, the London Philharmonic and more than two dozen plays (1-800-876-2200).

Use a local ticket agency. In most European cities, ticket agencies handle seats for a number of theaters, so you can do one-stop shopping for a fee. Some city tourist offices provide a ticket service, usually for special festivals. Check to see if the city has an box office outlet for half-price, day-of-performance tickets. There's one in London in Leicester Square.

Go to the theater box office yourself. In Europe, the theaters, opera houses and concert halls tend to be in the heart of town, so it is usually no great inconvenience to stop by to see what's available. In some theaters, a percentage of tickets is held back for sale only on the day of performance. You may want to consider a standing room ticket, usually sold only an hour or two before the performance.