NumberingData
Verified Nov 1, 2026 · Source: NANPA CO Code Assignment Records

WATERLOO prefixes in area code 618

NANPA records 4 assigned NXX blocks to rate center WATERLOO in area code 618, 0.5% of the 786 blocks assigned in the code. A rate center is the billing geography a block is allocated to – NANPA truncates the name to ten characters, so read it as a NANPA label rather than a town. 2 holders hold those blocks, the largest being T-MOBILE USA, INC. (2), HARRISONVILLE TEL. CO. (2). The earliest assignment on record here is 2010-07-30 and the most recent 2023-08-11. 2 of them are in thousands-block pooling, so those prefixes are shared between carriers in 1,000-number lots. The same rate center name also appears in area codes 260, 315, 319, 864 – overlay codes cover the same geography, so a rate center is served by all of them.

4 assigned blocks – 0.5% of 618
2 holders of record
2 of them pooled in 1,000-number lots

Prefixes assigned here

PrefixHolder of recordAssignedPooledIn service
618-504 T-Mobile T-MOBILE USA, INC. 2010-07-30 yes yes
618-938 HARRISONVILLE TEL. CO. – no yes
618-939 HARRISONVILLE TEL. CO. – no yes
618-986 T-Mobile T-MOBILE USA, INC. 2023-08-11 yes yes

The holder is who received the block from the numbering administrator. It is not necessarily the carrier serving a given number: numbers move with their owners, and a pooled block is shared.

Who holds the blocks

HolderBrandBlocksShare here
T-MOBILE USA, INC. T-Mobile 2 50%
HARRISONVILLE TEL. CO. – 2 50%

Same rate center in other codes

Overlay codes cover the same geography, so one rate center is served by all of them.

Frequently asked

Which prefixes belong to WATERLOO in area code 618?

4 blocks: 504, 938, 939, 986. The table above gives the holder of each.

Which carriers have numbers in WATERLOO?

T-MOBILE USA, INC. (2 blocks), HARRISONVILLE TEL. CO. (2 blocks). These are the holders on record; the carrier actually serving a given number can differ, because numbers move with their owners.

Is WATERLOO a city?

It is a rate center – the unit NANPA allocates number blocks to. Its name is abbreviated to ten characters and is not necessarily a settlement: we print it as recorded rather than guess at the full name.

Other rate centers in 618

All 786 prefixes in 618