Check the Tanglewood schedule by visiting the Boston Symphony Orchestra website and clicking "Tanglewood," then the link to view the season schedule to get a current listing of events. Select one of the "rehearsal" listings that suits your schedule (see Resources below).
Call Ticketmaster's Boston fine art's line at (800) 347-0808. Be sure to call during their regularly scheduled assistance hours of Monday through Friday from 9 a.m. to 9 p.m., Saturday from 9 a.m. to 8 p.m. and Sunday from 9 a.m. to 7 p.m. Eastern Standard Time.
Press "1" to purchase tickets. This brings you to the automated system. Say "Agent" or "Let's move on" when the automated system prompts you for a response. This will bring you to a live ticket agent who will assist you in selecting the open rehearsal performance date and time.
Make sure you tell the agent you are interested in the Tanglewood open rehearsal tickets, not the Tanglewood Music Festival's general performance.
Expect to pay anywhere from $50 to $100 for regular seats and about $20 for lawn tickets. You'll need a credit card to make your purchase so have your credit card handy when you call.