Android says "No SIM": what to check

Start with the exact message and what happened just before it appeared. A No SIM warning during a new phone or eSIM setup raises an activation question. The same warning on a line that had been working normally gives you an earlier working state to compare against. If the warning comes and goes, keep a record of both states.

This guide covers a missing or inactive SIM, including an eSIM that has not become available. If the phone identifies the carrier but the real problem is weak reception, that is a different troubleshooting path.

First check the line itself

On a Pixel, open Settings > Network & Internet > SIMs, choose the carrier and check Use SIM. Google’s SIM troubleshooting includes an inactive line among the explanations for a gray carrier name accompanied by a No SIM message. If the intended line is off, enable it and see whether the message changes.

For a Galaxy, Samsung’s SIM guide describes Settings > About phone > Status information > SIM card status. Check whether the Network field names a carrier. Menu names vary, so use the SIM settings available on your model when that path is different.

With two lines, make sure you know which one the warning refers to. A working second line does not show whether the first one is active or available.

If the intended line still is not recognized, restart normally. Samsung includes a restart before physical-card checks. Return to the same SIM screen afterward instead of changing several network settings at once.

If you use a physical SIM

Turn the phone off before removing the card. Google’s SIM installation instructions begin with the phone powered off. Use your model’s diagram to identify the correct tray and eject hole.

Remove the tray with the proper eject tool and keep the tool straight. Do not force a stuck tray or insert the tool into another opening. Check that the card sits in the orientation shown for that phone, since contact direction is not universal. A bent card or visibly damaged tray needs attention rather than extra pressure.

If the card is dirty, gently wipe it with a soft, dry cloth. Reinsert it only when the card and tray are dry and the card is seated correctly. These handling precautions follow Samsung’s linked guide. Ask the carrier for a replacement if the card is damaged, and get help with a tray that will not close normally.

After the phone starts, check the same SIM status again. One careful reinsertion is enough for the comparison. Repeating the removal several times after nothing changes adds little useful information.

If you use eSIM or recently transferred service

There is no card to reseat. The relevant checks are whether the phone supports the carrier’s eSIM service, whether the plan has been added and whether activation completed. Google’s SIM and eSIM guidance makes support dependent on both the phone and carrier.

Follow the carrier’s instructions for the exact activation or transfer you started. Do not erase an existing eSIM simply to experiment. If the previous phone is still available, tell support whether service remains active there and where the transfer stopped.

Samsung notes that a carrier’s SIM-protection service can prevent activation on a new device. Ask the carrier to check that through its verified support channel rather than switching off account protections speculatively. Google also directs persistent eSIM transfer problems to the carrier.

Use one comparison to choose who should investigate next

If you have access to another compatible phone or another compatible active SIM with the owner’s permission, the comparison can narrow the support route. Confirm compatibility with the carrier when it is uncertain.

Result	Next place to investigate
The original physical SIM also fails in another compatible phone	Ask the carrier to check the card and activation.
A known-working compatible SIM works elsewhere but repeatedly is not recognized in this phone	Ask the phone manufacturer to assess the phone-specific problem.
No comparison device or SIM is available	Contact support with the exact message, affected line and checks already completed.

For activation or transfer trouble, give the carrier the phone model, affected line and the stage where setup stopped. Share an IMEI or EID only through a verified private channel when support requests it. Those identifiers may be useful privately, but they do not belong in a public screenshot. If the phone itself needs repair, prepare your data before handing it over.