TL;DR: The best data provider for Belgium B2B outbound is a stack of providers, because Belgium is the weakest Benelux country for phone data. Only 16 of 40 Kaspr numbers for Belgian contacts passed our basic checks in October 2026. A full waterfall on 461 senior Benelux contacts still found usable mobiles for 85% of them. Persona matters more than provider: in our first benchmark (15,000 enrichments run in 2025 and 2026, published May 2026), law firm partners came back with 32.4% landlines and mid-managers with 1.9%. Stack providers, filter the persona, and check every number before your team dials.
40%.
That is the share of Kaspr numbers for Belgian contacts that passed our basic checks in October 2026. In France the same tool passed 74%. In the Netherlands, 65%.
Belgium looks like it should behave like its neighbours. It does not. More landlines. More cross-border workers on French or Dutch mobiles. More firm switchboards filed as "phone".
Answrd is part of Profitbl, which runs cold calling campaigns across Europe. We enrich Belgian lists and dial them on live campaigns. Here is what each provider found in Belgium, what reached the person, and how to build a stack that works.
Which data provider is best for Belgium phone numbers?
No single provider covers Belgium well, so the best setup is a waterfall. On 461 senior IT and security contacts in the Netherlands, Belgium and Luxembourg (50 to 249 staff), our October 2026 waterfall found a usable mobile for 392 people, or 85%.
Here is the short version, from our October 2026 data:
- Kaspr: first step. Found 225 usable mobiles on the 461 Benelux list (49%). Only 16 of 40 Belgian numbers passed our checks across all campaigns (40%).
- Tomba: cheapest second step. Found 31 usable of 236 Benelux contacts Kaspr missed, for USD 1.78 in total.
- Eficia: the big gap filler. Found 133 usable of 205 contacts left on the same list (65%).
- FullEnrich: strong on senior security people in the Netherlands and Belgium. Found 14 of 15 on one NL/BE list.
- Lusha: weak in Benelux for us. 27 billed hits on a senior list gave 1 usable own-country mobile.
Every provider after Kaspr ran on the contacts Kaspr had already missed. Read their rates as "what was left" after Kaspr.
Why is Belgian phone data harder than Dutch or French data?
Belgian data is harder because more of it is landlines, switchboards and mobiles from the wrong country. Kaspr's Belgian pass rate (40%, n=40) was the lowest of any big country we measured in October 2026. Only Ireland (10 of 22) and Luxembourg (0 of 13) came out near it or below.
Two things drive it.
Cross-border numbers. Many people who work in Belgium live in France or the Netherlands, and the other way round. Providers return their private French or Dutch mobile. It is a real number. It is also a personal phone.
On our Benelux waterfall, 33 of Eficia's failed numbers came from the wrong country. Another 20 contacts had only a mobile from a neighbouring country, mostly Luxembourg staff on Belgian or French numbers.
Directory data. Bar registers, chambers of commerce and trade bodies list the firm's main line as the contact. Enrichment tools find that number and log it as "phone". That hits some job titles far harder than others.
If you sell into the Netherlands too, the picture is calmer there. See why every provider works in the Netherlands. For the cross-border problem at its worst, read the Luxembourg pitfalls. For the French side of the border, see the best data providers for France.
Why does persona matter more than provider in Belgium?
Persona matters more because the same providers return clean mobiles for some job titles and switchboards for others. Our 2025 to 2026 data showed it plainly, on Belgian contacts:
- 784 mid-management contacts in French-speaking Belgium: 93.9% Belgian mobile format, 1.9% landlines.
- 37 law firm partners: 67.6% Belgian mobile format, 32.4% landlines.
- 60 staffing founders and CEOs: 77.6% mobile, 22.4% landlines.
- 27 contacts from an executive network list: 79.2% mobile, 20.8% landlines.
- 36 hospital C-suite contacts: 90.9% mobile, 9.1% landlines.
The mid-managers and the law firm partners ran through the same waterfall. The cause sits upstream of any provider. Mid-managers are active on LinkedIn, so their mobiles show up in the sources providers scrape. Partners and founders show up in directories, so the firm's main line wins.
Filter the list by persona before you spend a credit. Tighter title bands and company size bands give you a smaller list with far fewer landlines. Most Belgian teams spend more time choosing tools than choosing people. The data says the people matter more.
One catch. "Mobile format" means the number looks like a Belgian mobile. It says nothing about who answers it.
How many Belgian mobiles reach the right person?
About 1 in 4 dialled usable mobiles reaches the right person across our European campaigns. Our first benchmark, published in May 2026, promised to measure this. Now we have.
Kaspr numbers reached the person on 301 of 1,071 dials (28%, October 2026). Eficia numbers reached the person on 60 of 233 dials (26%). The rest rang out, went to voicemail or reached someone else.
For Belgium alone, the sample is small. Of 19 Kaspr numbers we dialled for Belgian contacts, 8 reached the person. That is too few to call a Belgian rate.
Across countries, most numbers that pass a format check still fail on the phone. For more on why, read why Lusha and Kaspr mobiles reach the wrong person.
How did each provider do on Belgian and Benelux contacts?
Each provider did one job well and others badly. Remember that every provider after Kaspr only saw the contacts Kaspr missed.
Kaspr
Kaspr is our first step, and it is where most Belgian numbers come from. On a fresh list it found 225 usable mobiles of 461 senior Benelux contacts (49%, October 2026). On Belgian contacts across all our campaigns, 16 of 40 numbers passed our checks (40%). We have dialled Kaspr numbers on our campaigns, and 8 of 19 Belgian ones reached the person.
Tomba
Tomba is the cheapest step per usable number we have found. On the 236 Benelux contacts Kaspr missed, it found 31 usable mobiles for USD 1.78 in total (October 2026). It bills on hits only. Benelux and France are its best markets in our data. It found 0 of 11 on German and Belgian public-sector leaders after Kaspr.
Eficia
We use Eficia in our own stack. On the 205 Benelux contacts still missing after Kaspr and Tomba, it found 133 usable mobiles (65%, October 2026). Of its failed numbers, 33 came from the wrong country.
Across all campaigns, 471 of 503 Eficia numbers passed our checks (94%). It costs about USD 0.27 per number.
FullEnrich
FullEnrich is strong on senior security people in Benelux, even after Kaspr. On one NL/BE list it found 14 of 15. On a wider NL/BE/LU senior security list, 38 of 52 (October 2026). It costs about USD 0.75 per usable number.
On 11 German and Belgian public-sector network leaders that Kaspr missed, FullEnrich found a usable mobile for 3 of 11 contacts. Tomba found none. Our DACH enrichment post has the public-sector numbers. We ran FullEnrich through looot, the data gateway we use. It found only 1 of 48 on our big Benelux run. That was a credit problem in our setup, so we do not count it against FullEnrich. After Eficia, it mostly re-finds the same numbers.
Lusha
Lusha did poorly on Benelux senior contacts after Kaspr. It returned 27 billed hits from 58 lookups. Only 1 was a usable own-country mobile, plus 1 that matched the wrong person.
That works out to about USD 20 per usable number (October 2026). Most hits were foreign mobiles and direct lines. We have dialled Lusha numbers on our campaigns, and in Benelux we would not pay that price again.
The rest
Prospeo found 2 of 66 on the Benelux list for USD 21.45. AI Ark found 0 of 66, with hits mostly from neighbouring countries. A tier of six cheap providers found about 3 usable numbers across roughly 250 senior European contacts, mostly US numbers for US-based people. We dropped all six.
Wiza, Zeliq and ContactOut (2025 to 2026)
Our first benchmark ran on a Clay waterfall. We cancelled Clay on 2026-04-22 and now run our own waterfall, built in Claude Code.
On the 784-contact Belgian cohort in the earlier runs, Wiza took 56.6% of phone wins, Zeliq 29.6% and ContactOut 10.3%. Those shares measure position in the waterfall more than quality, because the first provider sees every contact.
Wiza and Zeliq held clean mobile formats on their wins. ContactOut looked weaker on senior people at small firms, where LinkedIn profiles often list a firm switchboard. We have not dialled these in October, so we have no reach rate for them.
How we measured
Our first benchmark covers 15,000 enrichments run in 2025 and 2026 for 28 companies across 12 countries, including seven Belgian cohorts with more than 1,000 contacts. It measured fill rate and number format. Our October 2026 data adds dial outcomes from live campaigns and the providers we ran through looot from 2026-10-07 to 2026-10-22. "Usable" means a mobile in the contact's own country that we had not already flagged as bad.
Two caveats stay. First, waterfall position bias: later providers only see the contacts earlier ones missed, so their rates look lower than they would alone. Second, small samples: Belgium-only dial counts are low, and we give the n every time. The full study lives in our European B2B data enrichment report.
How should you build a Belgian phone stack?
Keep the providers you have, add one or two that are strong where they are weak, then check every number before the team dials. Here is what we would do for Belgium:
- Filter the persona first. Mid-managers and operations leads at mid-market firms give you mobiles. Partners and founders give you switchboards.
- Run Kaspr or your current tool first. Expect about half the list on senior Benelux contacts.
- Add Tomba next. It is cheap and does well on Benelux.
- Add Eficia to fill the big gap. On our list it found 65% of what was left.
- Add FullEnrich for senior security and IT. If you already pay for Lusha, test it on your own Belgian list before you buy more credits.
- Throw out wrong-country mobiles. A French or Dutch mobile for a Belgian contact is usually a personal phone.
- Check every number before you dial. Format checks catch the junk. They cannot tell you who picks up.
We explain how to order the steps and why the hit rate misleads in our guide to waterfall enrichment for phone numbers.
More providers means more numbers. More numbers means more wrong ones. That is why the last step matters most. Answrd checks the numbers your waterfall found and returns the ones that pick up, with wrong and dead ones flagged. Your first 100 numbers are free.
What about GDPR when you call Belgian numbers?
Belgium enforces GDPR through its Data Protection Authority. GDPR asks you to keep personal data accurate. A private French mobile filed as a business number for a Belgian manager is a hard record to defend. Log which provider found each number, take out wrong-country mobiles, and check local rules before you call.
Frequently Asked Questions
What is the best data provider for Belgium?
No single provider wins in Belgium. A seven-provider waterfall led by Kaspr, Tomba and Eficia found usable mobiles for 85% of 461 senior Benelux contacts in October 2026.
Does Kaspr work in Belgium?
Yes, but Belgium is its weakest big country in our data. 16 of 40 Belgian Kaspr numbers passed our checks (40%), against 74% in France, in October 2026.
Is Lusha good for Belgian phone numbers?
Not in our data. On a Benelux senior list in October 2026, 27 billed Lusha hits gave 1 usable own-country mobile, about USD 20 per usable number.
Why do I get so many landlines for Belgian contacts?
Directories list the firm's main line for partners and founders. In our first benchmark, 32.4% of numbers for 37 Belgian law firm partners were landlines, against 1.9% for mid-managers.
Why does my Belgian contact have a French mobile?
They likely live in France and work in Belgium. That number is usually a personal phone. We count it as a miss and take it out.
How many Belgian mobiles reach the right person?
Our Belgian dial sample is small: 8 of 19 Kaspr numbers reached the person. Across Europe, about 1 in 4 dialled usable mobiles reached the right person in October 2026.
Check your Belgian numbers before the next call block
The best data provider setup for Belgium B2B outbound is a short stack: filter the persona, run a few providers and throw out wrong-country mobiles. Then check every number before you dial.
Test 100 numbers free, no card needed. If you would rather talk it through, book a 15-minute call.