วิธีรักษาสายเบอร์โทรศัพท์สหรัฐฯ ให้อยู่ในสภาพพร้อมใช้งานเมื่อเดินทางไปต่างประเทศในปี 2026 | MollySIM

---

To keep your US phone number active abroad, compare the card price with the ongoing renewal bill. The lowest monthly price does not come with the lowest purchase price. You also need to distinguish a plan running out from the number itself expiring.

For US number 保号, the aim is to preserve a usable native US number while you are overseas. This guide compares MollySIM's options, explains the stated US SIM number expiry rule, and gives you a routine for checking the line before inactivity becomes a problem.

The three clocks that matter

Plan expiry: your allowance has a deadline

Lyca Mobile US plans have a 30-day allowance period. Lyca's published terms state that plan expiry alone does not cancel the number, and a top-up restores service. That distinction does not mean you can leave an expired plan untouched indefinitely: the separate non-use rule still matters.

T-Mobile's listed plans run on a monthly cycle. Budget for the monthly charge and check the renewal status. Do not apply Lyca's inactivity deadline to T-Mobile; the supplied T-Mobile information does not specify a corresponding number-expiry period.

Number and SIM expiry: Lyca's non-use deadline

Lyca's published terms state that the SIM and its assigned number expire after 60 consecutive days of non-use. Track the last actual use separately from the plan's renewal date. A payment record tells you about funding; it does not, by itself, establish what the carrier treats as use.

The supplied terms do not define which individual activities reset that deadline. Treat a successful call or message as a practical service check, and confirm the qualifying-activity requirement with the carrier before relying on a minimal-use strategy.

Carrier account closure: a separate question

Keep account closure separate from both an expired allowance and Lyca's stated SIM-and-number expiry. The supplied information gives no independent account-closure timetable or list of closure triggers. There is therefore no supported extra grace period to add to your calendar.

If the account shows a closure notice, ask the carrier what it means for your number. Do not assume the statement about topping up an expired Lyca plan also promises recovery after number expiry or account closure.

What using the line means abroad

For T-Mobile plans other than $15/mo, there is no cellular voice or SMS roaming outside the US. Calls and SMS work only through Wi-Fi Calling on Wi-Fi, and only with US numbers. You can call and receive calls from US numbers and receive US SMS, including bank codes, this way.

For a practical check, connect to Wi-Fi, enable Wi-Fi Calling, and try a call with a US number. You can also check receipt of a US SMS. Do not treat seeing a network name as proof that these services work. Use the Wi-Fi Calling traveller guide when preparing your setup.

The $15/mo T-Mobile option is the only listed T-Mobile plan with cellular roaming: it includes 1GB China roaming and free incoming. That is a specific reason to consider it beyond number retention.

Outside the US, Lyca's plan allowance—data, calls and SMS—needs Wi-Fi Calling switched on. Its SIM can register on local towers abroad, but registration alone does not give you the allowance. Its listed data is US data; do not budget it as overseas cellular data.

Using data on the plan is another service check where that data is available. It is not a documented guarantee of resetting Lyca's inactivity clock. If you also need travel internet, distinguish that requirement from number retention with the data-only versus voice and SMS guide and travel data budgeting guide.

Compare card prices and first-year costs

For each US option, the first-year comparison is card price + 12 monthly or 30-day renewals. These figures explicitly ignore fees and discounts. For Lyca, this is a comparison using 12 renewals of 30 days, not a claim that those renewals equal a calendar year.

T-Mobile $5/mo has the lowest first-year total under this formula. T-Mobile $3/mo has the lowest ongoing monthly charge. Decide whether your priority is the initial comparison or the continuing bill, and whether the allowance fits your use.

For completeness, the Hong Kong alternatives use different periods and currencies. They provide Hong Kong numbers, so they cannot substitute for a US number requirement.

The longer-duration cards are listed for comparison, not assigned invented monthly charges. See Three Hong Kong if that product's duration and allowance match your separate Hong Kong requirement.

Lyca caveats that change the maths

Lyca's published terms specify a 5% regulatory recovery fee on website purchases, including auto-recharges, and 10% off when auto-renewal is activated. The table excludes both. Check the charged renewal amount before setting your budget; do not simply subtract the fee percentage from the discount percentage and assume the result applies to every purchase.

The $15 plan's international calling allowance also has boundaries. Under Lyca's terms, “unlimited international calls” covers the first 10 dialled numbers per country, excluding Morocco IAM/Wana and Israel prefixes 97256/97259. Choose it for relevant usage rather than assuming the higher price buys a different retention rule.

A reminder routine that works

1. Record the starting state. MollySIM cards are activated before shipping. Save your number, plan, renewal date and last successful service check; do not assume delivery starts a fresh inactivity window.
2. Tie a check-in to each renewal. Use the monthly or 30-day cycle as your reminder rhythm. For Lyca, also keep a reminder comfortably before 60 consecutive days since your last confirmed qualifying use. Confirm what qualifies with the carrier.
3. Check the account and the line. Review payment success, plan status and any carrier notices. Enable Wi-Fi Calling abroad, test an available call or SMS function, and record the result. Investigate a failed check rather than marking it complete.
4. Set the next reminder immediately. Keep the renewal date and activity record distinct. Auto-renewal can handle payment, but your check-in should still verify that service works.

If you need a Hong Kong number instead

The Hong Kong number preservation and SMS card costs $27.49, with maintenance of about HK$15/year, and keeps an HK number for global roaming SMS. Keep those currencies separate when comparing it with the US plans.

Hong Kong's OFCA requires real-name registration before prepaid service can activate. Complete that requirement; the general pre-shipping activation arrangement does not remove it. A foreign passport is among the accepted documents.

FAQ

Does an expired Lyca plan immediately cancel my number?

No. Plan expiry alone does not cancel it, and a top-up restores service. The separate 60-consecutive-day non-use expiry still applies.

Is an automatic renewal enough to prove use?

The supplied terms do not establish that. Confirm qualifying activity with Lyca and keep a service-check record alongside payment records.

Can I receive US bank messages abroad?

T-Mobile's non-$15 plans receive US SMS through Wi-Fi Calling on Wi-Fi abroad. For bank-specific considerations, read US numbers for bank verification.

Can I order an eSIM instead?

Every physical card can also be delivered as an eSIM. Write eSIM in the order note to receive the activation QR code by email.

Can I return an activated card if I change my mind?

Activated cards have no change-of-mind refunds. If something is wrong with the card, support reviews it individually; no particular outcome is promised.

Two sensible picks

Choose T-Mobile $5/mo for the lowest listed first-year comparison, or T-Mobile $3/mo for the lowest continuing monthly charge. Both require Wi-Fi Calling for calls and SMS abroad. If Lyca's allowances better fit your usage, compare Lyca Mobile US while keeping its non-use deadline in your routine.