NPI Portal NPI Lookup & Verification

Marcelyn Opal Billy

Marcelyn Opal Billy is a Social Worker provider (Social Worker) practicing in Oceanside, CA, registered in the NPPES registry with NPI 1538840939 since 2023. Practices at Milestone House (listed at the same practice address in NPPES).

✓ Active NPI ✓ Valid NPI checksum Sole proprietor

NPI 1538840939
Entity type Individual (Type 1)
Name Marcelyn Opal Billy
Sex Female
Practice address Oceanside, CA, 92054
Phone 7604336361
Enumeration date 2023-07-27
Last updated in NPPES 2025-10-15

Street address withheld — NPPES sole-proprietor addresses can be home addresses. See our data policy.

Taxonomy & licenses

Taxonomy code Specialty Primary License State
104100000X Social Worker Primary ASW110331 CA
Copy-ready billing details
Provider: Marcelyn Billy
NPI: 1538840939
Taxonomy: 104100000X (Social Worker)
Address: Oceanside, CA, 92054

Other providers at this practice address

NPI Name Type Specialty Location
1538554530 Tina Jaworski Individual Clinical Social Worker Oceanside, CA
1609256403 Felisha Hampton Individual Rehabilitation Practitioner Oceanside, CA
1568094084 Milestone House Organization Adolescent and Children Mental Health Clinic/Center Oceanside, CA
1598378010 Joely Wiggins Individual Marriage & Family Therapist Oceanside, CA
1063009884 Beverly Boone Individual Mental Health Counselor Oceanside, CA
1639755986 Kayleigh Cole Individual Rehabilitation Practitioner Oceanside, CA
1497335038 Kelly Lyles Individual Social Worker Oceanside, CA
1700450269 Michelle Zambrana Individual Case Manager/Care Coordinator Oceanside, CA

Verify this record

Cross-check NPI 1538840939 against the authoritative CMS record: view Marcelyn Opal Billy on the official NPPES registry .

What is an NPI number?

A National Provider Identifier (NPI) is a unique 10-digit number that CMS assigns to every U.S. healthcare provider and organization under HIPAA. Type 1 NPIs identify individual providers; Type 2 NPIs identify organizations. The NPI appears on insurance claims, prescriptions, and credentialing paperwork, and never changes — even if the provider moves or changes specialty. Read the full guide or validate an NPI number.

Frequently asked questions

Where does Marcelyn Billy practice?
The practice location on file with NPPES is in Oceanside, CA. Providers can have multiple locations; NPPES lists the primary practice address.
What is the NPI number for Marcelyn Billy?
The National Provider Identifier (NPI) for Marcelyn Billy is 1538840939, a Type 1 (individual) record in the CMS NPPES registry.

Source: CMS NPPES (public data). Snapshot 2026-07-11. Provider record last updated 2025-10-15.