Is a 'Do NOT COMPETE' clause in an employment contract enforceable?

I'm afraid this is not a "yes" or "no" kind of question. The rules for enforcing non-completes in Washington turn on whether or not the restrictive covenants are reasonable in geographical scope, industry scope and time. You should confer with an attorney who works in this area, and he or she will need to read your employment agreement -- there might be arguments against enforcing your non-competition. If you go want to do a bit of research on this issue, go to Google Scholar and find these cases, which will get you started: Racine v. Bender, 141 Wn. 606, 615, 252 P. 115 (1927) Labriola v. Pollard Group, Inc., 152 Wn.2d 828, 100 P.3d 791 (2004) Good luck to you.

In WA, non-competes are enforceable depending on the limitations in time, scope and geographic location. You will need to see counsel to determine whether your particular agreement is limited enough for your prior employer to enforce it.

You should get legal advice before you go any further with your plan to quit and work for a competitor. If the non-compete clause is reasonable in duration, scope, and geography, there still must have been consideration given by the employer in exchange for your agreement not to compete. If the clause is in your employment agreement from when you were first hired, that is usually significant consideration. If the employer had you sign the non-compete clause sometime after you began working, it may not be enforceable (continued employment is not sufficient consideration). If it is enforceable, you could offer to pay the employer not to enforce the non-compete clause. I see that most often with professionals who take a book of business with them when they leave. They basically buy the book of business from the employer. Go get some advice before you change jobs.