How to hide your phone number from an ex you still have to contact

When a relationship ends but contact must continue (because of shared children, shared property, legal proceedings, or a workplace connection), one of the most practical questions is how to maintain that contact without giving up the privacy and control that comes with your real phone number. Shared pets can be one of those reasons; see who gets the dog after a breakup.

Your phone number is more than a way to reach you. It’s linked to your banking apps, your two-factor authentication, your social media accounts, and sometimes your address through reverse lookup services. Keeping it private from someone you don’t trust is a reasonable precaution, not an overreaction. The same applies when selling online to strangers.

Why number privacy matters

There are several distinct reasons why keeping a phone number private from a former partner can be important:

• Safety. In situations involving threatening or harassing behaviour, your phone number can be used to find you through carrier records, mutual contacts, or reverse lookup services. Keeping it private reduces this risk.
• Mental health. When you’re trying to maintain boundaries, receiving direct calls or messages at any hour, on your personal number, makes it harder to create the psychological separation you need.
• Boundaries after separation. Even in entirely non-threatening situations, having a dedicated contact point for co-parenting or property matters means you can “switch off” from those communications at the end of the day.
• Practical control. A relay number means you decide when to engage with incoming communications, rather than being subject to real-time contact at the other party’s discretion.

The common mistake people make

The most common approach people try first is to simply block the other party’s number. This works if you genuinely want no contact, but if you still need to communicate for co-parenting, legal, or property reasons, blocking creates its own problems. You may miss communications relevant to your children or your legal situation, and the other party’s lawyer could point to the blocking as a sign of non-cooperation. There are ways to stop someone texting without blocking them.

The second common mistake is using caller ID blocking. In Australia, you can dial a prefix before a number to suppress your caller ID for that call. But this only works for outgoing calls, doesn’t help with text messages, and doesn’t prevent the other party from using a call-tracing service. It’s not a privacy solution for ongoing situations.

Your options for a separate number

Second SIM card

The simplest hardware solution is a second SIM in a separate device, or a dual-SIM phone. You give the other party only this number. Your real number stays private.

This works well if the contact is infrequent. The limitations are:

• You need to carry a second device or have a dual-SIM phone
• You still receive all messages directly: there’s no filtering
• There’s no automatic archive unless you set one up manually
• If you change devices, you need to manage the number transfer carefully

VOIP numbers

Voice-over-IP services let you get a phone number that works over the internet rather than through a carrier. You can give this number out without exposing your real SIM number.

In Australia, options include Skype, Hushed, and various business VOIP providers. Google Voice is primarily a US service and is not available as a consumer product in Australia.

VOIP numbers have limitations for ongoing co-parenting use:

• Call quality can be inconsistent, particularly on mobile data
• Most free or consumer VOIP services don’t archive messages with metadata
• There’s no filtering: you receive everything directly
• Some services cancel numbers that go unused for periods of time
• Emergency services (000 in Australia, 911 in the US) may not be able to reliably locate you via VOIP

Why these options fall short for ongoing co-parenting

Both second SIMs and VOIP numbers solve the basic number privacy problem but don’t address the ongoing challenge of receiving inflammatory or distressing messages. In a high-conflict co-parenting situation, you’ll receive messages on your second number or VOIP that are designed to upset you, and you’ll receive them directly, without any buffer.

For someone trying to maintain their wellbeing while navigating a difficult co-parenting situation, this matters. Reading a distressing message at 11pm is harmful whether it arrives on your “real” number or a secondary one. The medium has changed but the impact hasn’t.

The relay approach

A relay number works differently from a second SIM or VOIP number. Rather than simply being a different number that connects directly to you, a relay number routes incoming messages through a processing layer before they reach you.

This means:

• Your real number is never exposed, now or in the future
• Incoming messages are filtered: hostile or threatening language is taken out before a message reaches you (see how AI message filtering works)
• Every original message is archived automatically, with full metadata
• You engage with co-parenting communications on your own terms, not in real time
• If the situation changes, if legal proceedings start, if you need a record for police, the archive is already there

Setting up the separation properly

Once you have a separate number, whether a second SIM, VOIP, or relay, the most important step is consistency. Never contact the other party from your real number. If you do, you’ve given it away regardless of the privacy solution you set up.

Practical steps:

• Give the other party your new contact details in writing, clearly stating this is the number for all future communications
• Block or mute your real number for any messages from the other party on your primary device, so you aren’t receiving duplicates
• If you have a written communication agreement, update it with the new contact details. If a parenting order names contact details, a lawyer can tell you whether anything needs to change
• Inform your lawyer and any relevant support services of the change
• If there are shared contacts who might give out your real number, consider letting them know it is private