TOMOKO HIRABAYASHI WILLIAMS MSN, RN, FNP-C
NPI 1255896262
Nurse Practitioner - Family in Irvine, CA
About Tomoko Hirabayashi Williams Msn, Rn, Fnp-c NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
TOMOKO HIRABAYASHI WILLIAMS MSN, RN, FNP-C (NPI 1255896262) is an individual family provider in Irvine, California, licensed in California (NP95037243) and active in the NPI registry since February 2019. She is enrolled in Medicare PECOS and is a graduate of Other (2018).
NPPES Registry Identity
Specialties & Licenses
Other Names 1
Accepted Insurance
Medicare Participation & PECOS CMS
Medicare enrollment, assignment, billing reassignment, and ordering and referring status from CMS.
Medicare Enrollment Status
Enrolled in Medicare and accepts Medicare assignment
Tomoko Hirabayashi Williams Msn, Rn, Fnp-c is registered in PECOS and agrees to accept the Medicare-approved amount as full payment. Medicare patients are not billed beyond the standard deductible and coinsurance.
Medicare Billing Reassignments
2Medicare enrollment records show Tomoko Williams reassigns Medicare billing to 2 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.
Duarte, CA 91010
- Reassigned Medicare billing, California enrollment
- 1,335 clinicians in this Medicare group
El Paso, TX 79915
- Reassigned Medicare billing, Texas enrollment
- 1,054 clinicians in this Medicare group
Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.
Areas of Expertise CMS Part B claims 16
Services this provider delivered to Medicare fee-for-service patients, from the CMS Medicare utilization data. Higher counts generally reflect more experience with a service; care delivered outside Medicare is not included.
Physician Visit Costs CMS claims · ZIP area
Typical Medicare office-visit costs in the 92618 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.
Medicare Quality Performance CMS QPP · MIPS
Performance in the CMS Quality Payment Program: the MIPS final score across four weighted categories, and the individual quality measures reported to Medicare.
Other Providers at the Same Location NPPES 20
Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.
IRVINE, CA 92618
IRVINE, CA 92618
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 Tomoko Williams's NPI number?
The NPI number for Tomoko Williams is 1255896262. It was assigned to this individual provider in the NPPES registry on February 4, 2019. The provider is also known as Tomoko Hirabayashi Sotomayor Msn, Rn, Fnp-C.
Where is Tomoko Williams located?
Tomoko Williams practices at 1000 Fivepoint, Irvine, CA 92618. The listed phone number is (800) 826-4673.
What is Tomoko Williams's specialty?
The primary specialty registered for this NPI is Nurse Practitioner, specializing in Family, with taxonomy code 363LF0000X.
Is Tomoko Williams enrolled in Medicare?
Yes. Tomoko Williams is registered in the Medicare PECOS system and accepts Medicare assignment, which means accepting the Medicare-approved amount as payment in full for covered services.
Which organizations bill Medicare for Tomoko Williams's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Tomoko Williams reassigns Medicare benefits to 2 organizations: City Of Hope Medical Foundation (Duarte, CA) and Texas Oncology PA (El Paso, TX). Each 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 Tomoko Williams's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.
What insurance does Tomoko Williams accept?
Health plans from Ambetter from Arizona Complete Health, Ambetter from Arkansas Health & Wellness, Ambetter from Louisiana Healthcare Connections, Ambetter from Superior HealthPlan and Ambetter of Oklahoma and 9 other insurers list Tomoko Williams as in-network in at least one marketplace plan. Coverage varies by plan and year; verify with the insurer or the provider before a visit.
When was this NPI record last updated?
The NPPES record for Tomoko Williams was last updated on February 6, 2026. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 9 months 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.
# Tomoko Hirabayashi Williams, MSN, RN, FNP-C · NPI 1255896262
Family physician in Irvine, California. Individual provider, active in the CMS NPPES registry since February 4, 2019.
## Identity
- **NPI:** 1255896262 (Entity type: Individual)
- **Enumerated:** February 4, 2019
- **Primary specialty:** Nurse Practitioner - Family · taxonomy 363LF0000X
- **State license:** NP95037243 (California)
- **Sole proprietor:** No
## Practice location
- **Address:** 1000 FIVEPOINT, Irvine, CA 92618-2621
- **Phone:** (800) 826-4673
## Medicare
- **Medicare:** Enrolled (PECOS); accepts Medicare assignment
- **Ordering & referring:** eligible for Part B labs & imaging, durable medical equipment, home health, power mobility devices
- **Bills Medicare through:** 2 organizations under Medicare reassignment (form CMS-855R): City Of Hope Medical Foundation (NPI 1871886366, Duarte, CA); Texas Oncology PA (NPI 1811944101, El Paso, TX) · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** Other, class of 2018
## Record status
- **NPPES last updated:** February 6, 2026
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Source: [NPI Profile](https://npiprofile.com/npi/1255896262) · Data from the CMS NPPES public registry.