Sprint Nextel has announced upgrades for dozens of its cell sites in the Seattle area, and the company is planning more upgrades in the next three months.

The 89 upgrades completed in the past 90 days increased capacity for 3G service, the company said in a press release. Sprint does have some 4G coverage in Washington, mostly between Everett and Tacoma along the I-5 corridor.

In the next 90 days, Sprint is planning an additional 87 upgrades. The Sprint network covers users of Sprint, Nextel, Boost Mobile and Virgin Mobile USA.

“Not only can our customers in west Washington get a great wireless experience, they can also get it without worrying about cost, thanks to Sprint’s unlimited plans,” said Jennifer Clark, Sprint’s director of business sales for Washington. “These upgrades are an important step in our overall Network Vision plan.”

Sprint launched the Network Vision plan last December to upgrade more than 22,000 cell sites around the country. From August through October, Sprint says 10,251 upgrades were completed.

Sprint also has an interactive map that shows the upgraded cell sites in Seattle and in other cities.