Flight
Sea-Tac is the closest airport to Seattle, if you're coming by air.
Hotel
The hotel is .7 miles from the aquarium, and a straight walk downhill to the waterfront. Returning to the hotel is a bit of a climb, though.
Hotel
The Hotel Max has a wide range of room options, with a 15% discount if you book through the link.
Discount Code - https://bit.ly/3wc39jy
Train
If you are staying at the Hotel Max or Hotel Monaco, exit at the University St. Station. The trip takes 35-40 minutes. Service is available from about 5 am through midnight daily. One-way adult fares range from $2.25 to $3.25 depending on how far you travel. Downtown Tunnel Stations include: Westlake, University St., Pioneer Square and International District.