Date: 25 Jun 2026

Location: Macquarie Park, Australia

#job-location.job-location-inline { display: inline; }

Company: Singtel Group

Optus is an Australian telecommunications company, delivering more than 11 million services to our customers every day across mobile, broadband and digital solutions.

The Technical Specialist - Mobile Voice Core is a senior hands-on technical role responsible for the end-to-end network design and delivery of mobile voice core solutions. Acting as a technical prime for assigned initiatives, this role owns network design activities from initial scoping through to implementation in the production environment.

This role may require participation in change windows outside of standard business hours.

Your day to day will consist of

Act as the technical lead for projects, overseeing end‑to‑end network design from scoping and high‑level design through to implementation and handover.
Develop, review, and approve detailed network design documentation, ensuring alignment with standards and target architectures.
Assess existing network infrastructure and deliver optimised, standards‑compliant design solutions based on business requirements.
Balance technical, operational, security, and financial considerations to recommend effective and scalable solutions.
Support delivery and change management activities, including configuration, deployment, testing, and Tier 3 fault resolution.
Define and maintain network standards, governance frameworks, and best practices while driving automation and continuous improvement initiatives.
Engage with internal stakeholders and external vendors as a trusted technical advisor, providing strategic input and alignment.
Communicate complex technical concepts clearly, building strong relationships and capability across teams.

What makes you perfect for the role

8+ years’ experience in telecommunications, including senior-level experience in mobile voice network design.
Strong expertise across mobile network environments, including LTE and 5G technologies.
In-depth knowledge of core protocols such as SIP, SDP, RTP, Diameter, HTTP(S), and H.248.
Proven experience with IMS architectures and implementations, with Ericsson IMS knowledge desirable.
Hands-on experience with network testing tools, monitoring platforms, and operational methodologies.
Familiarity with APIs and automation tools (e.g. Ansible, GitLab pipelines) to support modern network solutions.
Excellent communication and stakeholder engagement skills, with the ability to simplify complex technical concepts and work effectively across teams and senior leadership.

What’s in it for you?

Competitive remuneration and employee discounts. Make life easier (and more affordable) with $80 monthly credit and 25% off Optus products and unique shopping discounts with our retail partners.
Competitive leave policies, including additional 'Connected’ days to focus on culture, family, health, community, or whatever’s important to you.
We support growing families with inclusive, carer-neutral paid Parental Leave of up to 16 weeks.
Direct your own development and build future-ready skills with Optus U’s industry-focused micro-credentials, developed with La Trobe and Macquarie Universities.
Build meaningful connections through employee-led networks and diversity initiatives including Culture Connect, Elevate Women, Disability Network and Express Yourself (LGBTQIA+).
Put your wellbeing first with free access to counselling and support services, 24/7 — in-person, by phone, SMS, or video.

At Optus, we are strengthened by others and that means valuing diversity and saying ‘yes’ to embracing individual differences. We are committed to ensuring that our application process provides an equal employment opportunity to all job seekers, including individuals from diverse gender, cultural and linguistic backgrounds, individuals with a disability, individuals identifying as being part of the LGBTQIA+ community, individuals who may have served in the armed forces or who identify as Aboriginal and/or Torres Strait Islander. We also want to do our best to make our recruitment process inclusive. If you require any adjustments or accessibility support to participate fairly and equitably in the recruitment process, please email AccessibleRecruitment@optus.com.au or call 1800 309 170. We're here to help.

For more information on Diversity, Inclusion & Belonging at Optus, please visit https://www.optus.com.au/about/inclusion-diversity