On average, listings lease in the $20's per square foot per year. The SeaTac submarket is seeing a a rise in rates. In the last 3 months, the median rate went up $21 per sqft per year.
Compared to the rest of the Seattle Metropolitan Area market, the SeaTac submarket has smaller rates, so you should have no trouble finding a great deal in this depreciated region.
In the last 90 days, 5 listings have been posted online, which means new availabilities are probably leasing quickly. You'll want to be prepared to tour spaces as quick as possible. About 80% of the listings in the SeaTac are subleases, so you might be able to snag a great spot on a short term. There aren't many listings below 2,000 square feet available, so finding a space for a small business might be tough.
Even though the median size is 3,420 sqft, there are still 0 new listings below 2,000 sqft. Most buildings in this market are around 3 floors. Most buildings in this market were built in 1979 and are Class B.