Yes, you can drive to Whidbey Island without a ferry. To drive onto the island, you'll need to drive up the coast of the mainland and cross onto Whidbey Island via the Deception Pass Bridge on the northern tip of the Island. Whidbey Island is approximately 55 miles long, so if you are coming from Seattle and your final destination is on the southern end of the Island, the ferry can shorten the road trip by up to 90 minutes.