Seattle isn’t as big as NYC, LA, Chicago, or even SF for that matter but the public transit is still reasonable. If you’re just staying in the city and exploring, you don’t need a car because there are a lot of public and private options to take. If you want to go outside of Seattle for the hiking, national parks, mountains, lakes, nearby cities, islands, and skiing, then you’ll want to rent a car. Above is a picture of Bloedel Reserve on Bainbridge Island; you can take a walk-on ferry or drive your car to get there.

Public

Link Light Rail (fast train) – Adult fares range from $2.25 to $3.00 depending on how far you travel.
King County Metro Transit (just buses) – Typical fares range between $2.50 to $3.25 for a single adult (depends on time and where).
Seattle Center Monorail ($2.25 one way) – You should totally ride this – it’s built for tourists, clean, has large windows, and gives you great views of Seattle (like when the bunny goes to Zootopia).

Private

Uber phone app: Overall, I find Uber to be cheaper in Seattle. Do fare estimate and be careful with surge pricing. Download the app and get a free ride by signing up here.
Lyft phone app: Sorry, no Lyft Line (carpool version) here but do the fare estimate and be careful with surge pricing too. Download the app and get free rides by signing up here.
Flywheel phone app: I haven’t had the best experience with them as it’s typically taxis picking you up but no surge pricing. Download app and use code X4ACYZ here to get $5 off.
Curb phone app: Works with licensed taxis on-demand, may not have surge-pricing, but fares are generally a little higher than Uber and Lyft but no surge pricing.
Pronto bikes: A bicycle sharing system with 500 bikes and 50 stations located throughout the city. 24-hour and 3-day passes with unlimited rentals are available at any Pronto kiosks. A trip begins when a bike is unlocked and ends when the bike is securely returned to any Pronto station. One- and three-day passes start at $8.
Taxi: There aren’t that many available taxis roaming around Seattle. Meters start at $2.50 with each additional mile costing an extra $2.50.
CartoGo: If you’re a cartogo member, we have this.
Zipcar: If you’re a Zipcar member, we have this too.

To and from the Sea-Tac airport

Taking the Link Light Rail between Sea-tac and downtown Seattle takes 35mins and is $3.00. Taking an Uber or Lyft is around 22mins (w/o traffic) and ~$32. Taking a taxi at the airport can run you to ~$40-$50 unless you book a flat-rate taxi ahead of time – try Eastside for Hire (licensed taxi service) which does a good $29 flat rate to Downtown.

Parking

A lot of parking in the heart of the city (Downtown) and popular Seattle neighborhoods costs money but then most on-street parking is free nights after 8pm in most areas (6pm in some), and all day on Sundays and holidays.