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Family SIM plans and multi-line discounts in the UK

Offers checked 23 September 2026

Five UK networks give a real discount for each extra line: O2 (20% off airtime with Multisave), Three (up to 20% with Connect Together), EE (£10 a month off extra SIM plans), Vodafone (£14 or £19 a month off with Vodafone Together) and BT (each extra Family SIM 20% cheaper). SMARTY Groups cost £15 a month per extra unlimited SIM. giffgaff, iD Mobile, VOXI and Lebara have no family discount. Sky shares spare data instead.

How family SIM plans work

There are three kinds of family deal. The most common is an add-a-line discount: you keep one full-price plan and every extra plan on the same account gets money off. O2, EE, Three, Vodafone and BT work this way.

The second kind is shared data. Sky Mobile pools unused data from every SIM on the account and lets any SIM draw from it. EE lets the account holder gift data between plans on the same account. Neither is a discount on the monthly price.

The third kind is simply separate SIMs on one bill with no saving. iD Mobile lets you manage several plans in one app. Tesco Mobile adds a small free perk per line rather than a price cut. giffgaff does not allow more than one SIM per account at all.

Each pay monthly line is its own contract. Networks normally credit check the account holder for every new line, and the account holder pays for every line. Vodafone's terms say each additional plan is subject to a standard credit check.

Contract end dates rarely line up. A plan added eight months after the first one ends eight months later. Discounts usually apply only to plans added after the first, so the order you join in matters, and some discounts stop or move if the first plan is cancelled.

Family offers by network

What each UK network offers when you put more than one line on an account. Prices change often: follow the link to check the current offer.

O2: Multisave

Discount per extra line

You get 20% off the airtime plan of each new eligible Pay Monthly connection added to your Multisave group. The first number is the 'lead connection' and is not discounted. The discount is on the airtime only, not the device plan. You can also add other O2 numbers to your group. If the lead number disconnects, the others keep their discount until they upgrade. Parents get network content controls and McAfee online security.

Saving
20% off the monthly airtime plan of every line after the first.
Lines
Up to 20 numbers in a Multisave group.
Eligibility
Pay Monthly O2 Refresh or SIM Only tariffs bought directly from O2, connected or upgraded in the last 28 days. Not Pay As You Go, sharer plans, business tariffs, older Standard Pay Monthly tariffs, wearables or Ultimate Plans. Connections bought through a third-party reseller can be the lead connection but get no discount. Cannot be combined with other promotional discounts; O2 applies the bigger one.
Example
O2's own example: a new connection with a £16 a month airtime plan gets £3.20 off, so the airtime costs £12.80 a month (as of 2026-09-23).
O2's official page O2 review and plans

EE: Multi-line discount

Discount and shared data

Add another plan to an existing EE account and that extra plan gets a monthly discount. One plan on the account always stays undiscounted (the 'qualifying plan'). The account holder can also gift data from any plan to any other plan on the same account with Data Gifting. EE sells Safer SIMs for children with parental controls and spend limits that cannot be switched off.

Saving
£10 a month off SIM only, Data SIM and Flex Pay airtime plans. 10% off pay monthly phone, tablet and laptop plans.
Lines
Not stated on EE's help page.
Eligibility
Existing EE customers, or new customers taking more than one plan at once. All plans must be on the same account. The discount comes off the extra plan's monthly payment only, not roaming or out-of-bundle charges. Annual price rises are worked out on the undiscounted price. If the qualifying plan is cancelled and only one discounted plan remains, the discount ends. Data Gifting works on Essentials, All Rounder and Full Works plans only.
EE's official page EE review and plans

Vodafone: Vodafone Together

Discount per extra line

If you have a qualifying Vodafone Pay Monthly plan (or Vodafone home broadband), each new eligible mobile plan you add gets a fixed monthly discount. The discount depends on the qualifying plan and the plan you add. It lasts 27 months on SIM only plans and 39 months on airtime plans bought with a phone. Existing discounted plans keep it for that period even if the qualifying plan is removed. New mobile plans come with Secure Net Mobile (parental controls) free for three months.

Saving
£14 a month off an additional 80GB plan. £19 a month off an additional Unlimited plan when the qualifying plan is also Unlimited.
Lines
Up to 10 additional mobile plans per account.
Eligibility
UK customers buying directly from Vodafone, not through a third party. Only new additional plans qualify; the discount is not applied to existing plans. Each additional plan is credit checked. Cannot be combined with other promotions. Annual price rises are not discounted. Transferring a plan to another person removes the discount.
Example
Vodafone's family page lists additional Unlimited (100Mbps) plans from £16 a month on a 24-month plan, rising to £18.50 on 1 April 2027 (as of 2026-09-23).
Vodafone's official page Vodafone review and plans

Three: Connect Together

Discount per extra line

Once you have a qualifying 12 or 24-month plan with Three, each additional plan added to the same account gets up to 20% off its monthly charge. The first plan is not discounted. For new customers buying several plans, the discount goes on the cheaper plan. The discount applies to airtime only, not device plans, and it continues after the additional plan's minimum term ends.

Saving
Up to 20% off the monthly airtime charge of each additional plan.
Lines
Up to 6 discounted additional plans. You can add more, but without the discount.
Eligibility
Consumer customers buying directly from Three, not through partners or affiliates. Qualifying plans: 12 or 24-month SIM Only, Airtime, Data SIM, Connect or Mobile Broadband plans. Not Pay As You Go or smartwatches. Cannot be combined with other offers, student plans or Friends and Family discounts.
Example
Three lists additional Unlimited data plans from £13 a month on a 24-month plan (as of 2026-09-23).
Three's official page Three review and plans

Tesco Mobile: Family Perks

Discount per extra line

When two or more pay monthly contracts sit on one account, each line picks one free monthly perk: extra data, bill credit, Clubcard points or money off Tesco Mobile Protect insurance. The size of the perk depends on the tariff price. There is no percentage discount and no shared data pool. Parental controls can be set to under 12s, under 18s or 18+ in My Account.

Saving
Per line, each month: 250MB to 1GB of data, or 50p to £2 off the bill, or 50 to 200 Clubcard points, or 75p to £2.25 off Protect insurance.
Lines
Up to 5 contracts on one account.
Eligibility
Pay monthly customers (phone or SIM only) who joined after 2 July 2012, with at least two eligible contracts on the same account. Pay As You Go is excluded.
Tesco Mobile's official page Tesco Mobile review and plans

Sky Mobile: Sky Piggybank (shared rollover data)

Shared data

Unused data on each SIM rolls into one Sky Piggybank at the end of the billing period. Any SIM on the account can draw from it in 1GB steps. Rolled-over data expires after 12 months. Unlimited data plans do not roll data into the Piggybank. Each SIM has its own data plan and Sky applies spend limits per SIM. We found no per-line price discount on Sky's own pages.

Saving
No monthly price discount. The saving is spare data that one family member can pass to another.
Lines
Rolled-over data can be shared with up to 7 SIMs on the account.
Eligibility
Sky Mobile pay monthly SIMs on the same account. Not available on Unlimited data plans.
Sky Mobile's official page Sky Mobile review and plans

giffgaff

No family offer

giffgaff has no family plan, shared data or multi-line discount. Its help centre says members cannot activate multiple SIMs on the same account; each SIM needs its own account. Activating a second SIM on an active account swaps your number onto the new SIM.

Saving
None.
Lines
One SIM per account.
Eligibility
Not applicable.
giffgaff's official page giffgaff review and plans

iD Mobile

No family offer

iD Mobile has no family discount or shared data. Its app lets you manage multiple plans in one place, but each plan is a separate contract at the normal price. iD's SIM only plans carry no annual price rises, which makes it easier to predict a household total.

Saving
None.
Lines
Not stated.
Eligibility
Not applicable.
iD Mobile's official page iD Mobile review and plans

SMARTY: Group plans

Discount per extra line

One person owns the group and pays for every SIM. There are two versions. Everyone Unlimited gives every SIM unlimited data at a flat price with one payment date. Mix and Match lets each member pick their own plan with 10% off for each member. The owner can add or remove SIMs each month and manage add-ons for every SIM. All SMARTY plans are 30-day rolling.

Saving
Everyone Unlimited: £20 a month for the owner, £15 a month per member. Mix and Match: 10% off per group member.
Lines
2 to 8 SIMs per group.
Eligibility
New and existing SMARTY customers. Members can keep their numbers with a PAC code.
Example
A family of four on Everyone Unlimited pays £20 + 3 x £15 = £65 a month for four unlimited SIMs (as of 2026-09-23).
SMARTY's official page SMARTY review and plans

VOXI

No family offer

VOXI has no family plan or multi-line discount. Each person has their own VOXI account. A parent can set up an account in a child's name, keep the login to monitor usage and content controls, and pay for it with their own card.

Saving
None.
Lines
One SIM per account.
Eligibility
Not applicable.
VOXI's official page VOXI review and plans

Lebara

No family offer

Lebara has no family discount or shared data. You can order an additional SIM, but it needs its own plan at the standard price. We could not confirm on Lebara's own pages how many SIMs one account can hold.

Saving
None.
Lines
Not verified.
Eligibility
Not applicable.
Lebara's official page Lebara review and plans

Utility Warehouse: Family SIM deals (Go Unlimited)

Discount per extra line

Take a Go Unlimited SIM and add up to three extra Go Unlimited SIMs free for the first three months. After that, each extra SIM costs the same as the first. Every SIM has its own unlimited data. Contracts roll monthly. Taking two or more SIMs also unlocks cheaper UW energy tariffs.

Saving
Three months free on each extra SIM. No ongoing per-line discount on mobile.
Lines
The first SIM plus up to three extra SIMs.
Eligibility
New and existing UW customers who also take broadband, energy or insurance from UW, unless UW offers Go Unlimited mobile-only through a sales channel it chooses.
Example
Go Unlimited is £13 a month. Extra SIMs are £0 a month for three months, then £13 a month each, so four SIMs cost £13 a month for three months and £52 a month after that (as of 2026-09-23).
Utility Warehouse's official page Utility Warehouse review and plans

BT Mobile: Family SIM

Discount per extra line

Family SIMs are several SIMs for one household paid from one account. Each additional SIM is 20% cheaper than buying it on its own. Every SIM gets its own allowance. The main account holder manages settings, usage and payments for all SIMs and pays every bill. BT broadband customers get £5 off BT plans. Note: an older BT help article says Family SIMs are only for existing Family SIM customers, while the current family SIM page sells them. Check at checkout.

Saving
Each additional SIM is 20% cheaper than a standalone SIM.
Lines
2 to 5 SIMs on the family SIM page.
Eligibility
BT Mobile pay monthly. The main plan has a 12-month minimum term. BT broadband customers pay less.
Example
BT's family SIM page shows two 4GB SIMs for £19 a month on a 12-month contract, or £14 a month with the BT broadband discount (as of 2026-09-23).
BT Mobile's official page BT Mobile review and plans

Virgin Mobile (Virgin Media O2)

No family offer

Virgin Mobile plans are no longer sold. Virgin Media says Virgin Mobile has moved to O2 and points customers to O2 and giffgaff plans. The old Virgin Mobile Family Plan page now redirects to O2 Multisave, so a family on the Virgin Media O2 group should compare O2 Multisave.

Saving
None on Virgin Mobile. See O2 Multisave (20% off airtime per extra line).
Lines
Not applicable.
Eligibility
Not applicable.
Virgin Mobile (Virgin Media O2)'s official page Virgin Mobile (Virgin Media O2) review and plans

Is a family plan the cheapest option?

  • The biggest multi-line discounts only apply when you buy directly from the network. O2, Three and Vodafone all exclude plans bought through resellers or affiliates. A cheaper deal bought elsewhere can still beat the discounted direct price, so compare the final monthly cost, not the percentage.
  • Separate SIM-only plans often win for small data users. A child who needs a few gigabytes is usually cheaper on a low-cost SIM-only plan of their own than on a discounted big-network plan, because 20% off a £16 airtime plan is still £12.80.
  • For four heavy data users on rolling contracts, SMARTY Everyone Unlimited is the simplest price: £65 a month for four unlimited SIMs with no long contract (as of 2026-09-23).
  • Discounts apply to airtime only. O2, Three and Vodafone do not discount the phone payment, and EE and Vodafone calculate annual price rises on the undiscounted price.
  • Some offers need another service. Utility Warehouse's free extra SIMs need broadband, energy or insurance from UW, and BT's lowest family price includes the BT broadband discount.

Separate SIM-only plans are often worth pricing against a family bundle: compare SIM-only deals.

Tips before you add a line

  • Put the plan you will keep longest first. On O2, EE, Three and Vodafone the first plan gets no discount, and cancelling it can end or move the discount on other lines.
  • Align contract end dates where you can. Adding lines months apart leaves you with staggered end dates, which makes switching the whole family at once harder.
  • Turn on parental controls for children's lines. O2, EE, Vodafone and Tesco Mobile all offer network content filters; EE Safer SIMs have controls that cannot be switched off.
  • Set spend caps or bars on children's SIMs so premium-rate calls and charge-to-bill purchases cannot run up the account holder's bill.
  • Check whether the family discount replaces a better promotion. O2, Three and Vodafone apply only one discount per plan.
  • Use shared data features before buying more data. EE Data Gifting and Sky Piggybank let one person's unused data cover another's overspend.

Family SIM plan FAQs

Which UK network has the best family deal?
It depends on how many lines and how much data. For unlimited data on rolling contracts, SMARTY Group plans cost £15 a month per extra SIM (as of 2026-09-23). On the big networks, Vodafone Together gives the largest fixed discount at £19 a month off an extra Unlimited plan, and O2 Multisave gives 20% off airtime on up to 20 numbers.
Can I mix pay monthly phone contracts and SIM-only plans on one family account?
Yes on most networks that offer a family discount. O2 Multisave, EE, Three Connect Together and Vodafone Together all cover both phone airtime plans and SIM-only plans. The discount applies to the airtime part only, not the phone repayments.
Does each line need a credit check?
Usually yes. Each pay monthly line is a new contract, and the account holder is responsible for paying it. Vodafone's terms state that every additional plan is subject to a standard credit check. Rolling SIM-only providers such as SMARTY do not tie you to a long contract.
Can my child have their own plan?
Yes. Children under 18 cannot sign a contract, so the plan normally sits on a parent's account. VOXI lets a parent set up an account in the child's name and pay for it. EE sells Safer SIMs from £9 a month on a monthly rolling plan with parental controls that cannot be switched off (as of 2026-09-23).
What happens if one person leaves the family plan?
Their contract still runs to its end date unless they pay to leave early. If the person leaving is on the first, undiscounted plan, the rules vary: on EE the discount ends if only one discounted plan is left, on Vodafone existing discounted plans keep their discount for the set period, and on O2 the others keep their discount until they upgrade.
What is the cheapest way to get SIMs for a family of four?
For four unlimited data users, SMARTY Everyone Unlimited costs £65 a month in total on a rolling contract (as of 2026-09-23). If most of the family use little data, four separate low-cost SIM-only plans are often cheaper than any family bundle. Compare our SIM-only deals by data allowance.
Can we share one data allowance?
None of the family offers we checked gives the whole family one shared data pool. Sky Mobile lets up to 7 SIMs on one account share rolled-over spare data, and EE lets the account holder gift data between plans on the same account. Every other network gives each SIM its own allowance.
Does giffgaff have a family plan?
No. giffgaff allows only one SIM per account, so each family member needs their own account and there is no multi-line discount.

Sources

Offers were checked against each network's own website on 23 September 2026.