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MASTERY MENTAL HEALTH PLLC
NPI 1356942064
Social Worker - Clinical in Mukilteo, WA

Active since November 09, 2020
627 5TH ST STE 200, MUKILTEO, WA 98275(206) 309-3839(425) 513-2329 Get Directions Write a Review

NPPES record last updated: November 9, 2020. Verified against the NPPES registry weekly; last sync: October 25, 2026.

About Mastery Mental Health Pllc NPPES

Official registry information on file with the National Plan and Provider Enumeration System.

MASTERY MENTAL HEALTH PLLC (NPI 1356942064) is a healthcare organization registered as a clinical in Mukilteo, Washington and active in the NPI registry since November 2020. The organization lists Geoffrey Michael Simkins, Owner/counselor, as its authorized official.

NPPES Registry Identity

NPI1356942064
Entity TypeOrganization
Primary Taxonomy1041C0700X
Legal Business NameMASTERY MENTAL HEALTH PLLC
Location Address627 5TH ST STE 200Mukilteo, WA 98275-1580
Mailing Address627 5th St Ste 200Mukilteo, WA 98275-1580 · (206) 309-3839
Phone(206) 309-3839
Fax(425) 513-2329
Organization SubpartNo
Authorized OfficialGeoffrey Michael SimkinsOwner/counselor · (360) 566-3722
Enumeration DateNovember 9, 2020
NPPES CertifiedNovember 9, 2020
✔ NPI 1356942064 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses 2

★ Primary SpecialtySocial Worker · ClinicalBehavioral Health & Social Service Providers
Taxonomy Code1041C0700X
Definition
A social worker who holds a master's or doctoral degree in social work from an accredited school of social work in addition to at least two years of post-master's supervised experience in a clinical setting. The social worker must be licensed, certified, or registered at the clinical level in the jurisdiction of practice. A clinical social worker provides direct services, including interventions focused on interpersonal interactions, intrapsychic dynamics, and life management issues. Clinical social work services are based on bio-psychosocial perspectives. Services consist of assessment, diagnosis, treatment (including psychotherapy and counseling), client-centered advocacy, consultation, evaluation, and prevention of mental illness, emotional, or behavioral disturbances.
Also ListedCounselorTaxonomy 101Y00000X
627 5TH ST STE 200, Mukilteo, WA 98275
Open in Google Maps ↗

Group Practice 1

Group TaxonomyThis provdier is a business group of one or more individual practitioners, all of who practice with the same area of specialization.193400000X MULTIPLE SINGLE SPECIALTY GROUP

Medicare Participation & PECOS CMS

Medicare enrollment, revalidation and the clinicians who bill Medicare through this organization, from CMS.

Medicare Enrollment Status

✔

Enrolled in Medicare (PECOS)

Mastery Mental Health Pllc is registered in the CMS Provider Enrollment, Chain and Ownership System (PECOS).

Medicare Revalidation Due Date

Revalidation due by October 31, 2026

Medicare-enrolled providers and suppliers confirm their enrollment information with CMS on a set cycle, every 5 years for most and every 3 years for medical equipment suppliers. CMS sets the due date for each enrollment.

StateEnrollment IDDue date
StateWashingtonEnrollment IDO20210115000399Non-DME Part B · Clinic/Group PracticeDue dateOctober 31, 2026
Source: CMS Revalidation Due Date List, October 2026 release.

Clinicians Billing Medicare Through This Organization

Medicare enrollment records show 1 clinician reassigns Medicare billing to Mastery Mental Health PLLC, which bills Medicare for the services this clinician delivers.

Clinician (1)

Geoffrey Simkins, MSW
Clinical Social Worker
NPI 1568703551
627 5TH ST STE 200
Mukilteo, WA 98275
(206) 309-3839
✔ PECOS✔ Accepts MedicareSame address

Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.

Frequently Asked Questions NPPES & CMS

Common questions about this NPI record, answered from the official NPPES registry and CMS datasets shown on this page.

What is Mastery Mental Health PLLC's NPI number?

The NPI number for Mastery Mental Health PLLC is 1356942064. It was assigned to this organization in the NPPES registry on November 9, 2020.

Where is Mastery Mental Health PLLC located?

Mastery Mental Health PLLC is located at 627 5th St Ste 200, Mukilteo, WA 98275. The listed phone number is (206) 309-3839.

What is Mastery Mental Health PLLC's specialty?

The primary specialty registered for this NPI is Social Worker, specializing in Clinical, with taxonomy code 1041C0700X.

Is Mastery Mental Health PLLC enrolled in Medicare?

Yes. Mastery Mental Health PLLC is registered in the Medicare PECOS enrollment system.

When is Mastery Mental Health PLLC's Medicare revalidation due?

According to the CMS Revalidation Due Date List (October 2026 release), the Medicare Non-DME Part B enrollment for this organization (Washington, Clinic/Group Practice) is due for revalidation by October 31, 2026. Medicare providers and suppliers revalidate their enrollment every 5 years, and medical equipment suppliers every 3 years. Confirm current requirements with your Medicare Administrative Contractor.

How many clinicians bill Medicare through Mastery Mental Health PLLC?

According to the CMS Revalidation Reassignment List (October 2026 release), 1 clinician (Clinical Social Worker) reassigns their Medicare billing to Mastery Mental Health PLLC. A reassignment is filed with Medicare on form CMS-855R, signed by both the clinician and the organization, and lets the organization bill Medicare and receive payment for the clinician's services. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.

When was this NPI record last updated?

The NPPES record for Mastery Mental Health PLLC was last updated on November 9, 2020. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 5 years ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.