0483, 0485, 0488, 0499: which operator in Belgium?

A number starting 0483, 0485 or 0488 was originally opened by BASE, now part of the Telenet group. A 0499 comes from Orange, a 0475 from Proximus. Since number portability, that is only an origin: the holder may have changed network without changing number. Only the 1399 database gives the current network.

A mobile prefix in Belgium is the first four digits, the 04 and the two that follow. Six digits remain behind it, so a million possible numbers per prefix: the five prefixes on this page cover five million (calculated 26 October 2026). That is a lot of people for a clue that predates number portability.

0483, 0485 and 0488: three prefixes opened by BASE

BASE is the mobile brand of the Telenet group, running on Telenet's own mobile network. It received the 0483 to 0489 block originally, according to the list of Belgian telephone prefixes on Wikipedia checked on 26 October 2026.

A call from a 0485 therefore tells you one thing only: someone, once, was given that number at BASE.

0499 and 0475: Orange on one side, Proximus on the other

The 0490 to 0499 block goes to Orange (own mobile network, plus the Walloon cable formerly VOO), the 0470 to 0479 block to Proximus (own copper, fibre and mobile). Astel adds reseller brands inside those blocks: hey! (an Orange brand, on the Orange network) for the first, Scarlet and Yoin (Proximus network) for the second.

Same logic, same caveat. A 0499 may well have been a Proximus customer for ten years.

Three public lists, three slightly different answers

I compared three sources on 26 October 2026, noting their dates. They agree on the essentials, not on the detail.

Checked 26 October 2026. The Astel page was last edited on 21 December 2024, the Qui Est Ce Numéro one dates from April 2026: sixteen months apart.

Two gaps deserve a pause. The detailed lists describe 28 of the 30 possible prefixes between 0470 and 0499: neither 0481 nor 0482 appears, yet the third source files "0480 to 0489" under Telenet. And Astel stretches each block to brands Wikipedia ignores, a reminder that a prefix gives the origin of a range, not the name on the bill.

Wikipedia says as much itself, with an example: a 0486 number opened at BASE moved to Orange and kept its 0486.

Why does the prefix tell you nothing since number portability?

Because the number follows its holder, not the operator. When a subscriber changes network, they keep all ten digits, and the prefix stays that of the operator who opened it. Porting a mobile number takes one working day in principle, according to BIPT (IBPT in French), the telecom regulator. The new operator handles the paperwork, the old contract ends, and the subscriber's friends notice nothing, since the number is identical. The result: the more portability gets used, the less the prefix informs, and it gets used a lot.

A worked example: if 5% of the numbers in a block of one million have changed network, that is 50,000 numbers whose prefix misstates their current operator. That percentage is a calculation assumption, not a measurement: to my knowledge no public figure for the porting rate by prefix exists. It is enough to show the scale of the problem.

Put differently, reading a prefix to guess a network is like reading a number plate to guess where the car is parked.

How do you check the current network of a 0485?

Type all ten digits into crdc.be, the 1399 database run by the NPA association. It is free, needs no sign-up, and the answer fits in one word: the network.

1. Enter the full number, for example 0485xxxxxx.
2. Read the network shown. It is the host network: a Scarlet number appears as Proximus, a hey! number as Orange, a BASE number as Telenet.
3. Do not look for a name. The database never returns the holder's identity.

Our guide which operator owns a Belgian number details the tool and its limits.

Brand, network, prefix: three labels for one number

The network shown by the 1399 database is not always the brand you are looking for, and neither is the prefix. Take a Scarlet subscriber: the bill says Scarlet, the database says Proximus, and the number may start 0475, 0499 or anything else if the line was ported in from elsewhere.

Brands and host networks as described in our article which operator owns a Belgian number, cross-checked against the lists of 26 October 2026.

The practical consequence: in a dispute or a complaint, the brand on the contract counts, not the network shown or the prefix.

Should you distrust a call from a 0485 or a 0488?

Not because of the prefix. A 04 number is an ordinary mobile, never premium-rate: those start with 09 or 070, and our article on premium-rate numbers in Belgium prices them. The useful signal lies elsewhere: in how the call behaves.

Four mistakes come up again and again:

• Concluding that a 0485 is "BASE telemarketing": the prefix proves neither the brand nor the caller's trade.
• Calling back a foreign number that rang once, out of simple curiosity.
• Trusting the displayed name without checking the full number.
• Reporting a mobile number to the operator behind the prefix, which may no longer be the right one.

To report, use the federal contact point. To block, our guide block a number on iPhone and Android gives the steps.

A Belgian number can lie, and the law deals with it

A fraudster abroad can make a Belgian number appear on your screen. The royal decree of 12 May 2024 requires operators to block those calls: from 1 September 2024 for landline numbers, from 1 December 2024 for mobiles, according to BIPT. The blocking is not perfect, and text messages are not covered.

The detail is in our article on number spoofing.

When the prefix is enough

When you only want to know whether a 04 is Belgian and mobile: yes, it is. That is all it guarantees.

To compare other blocks, see our sheets on the 0480 on the Telenet side and the 0497 on the Orange side, and the guide to the unknown number calling.