Samsung
Select Network Manually auf Samsung
Automatic network selection on Samsung phones picks a provider based on signal strength and roaming agreements, not on your tariff costs.
Near a border or while traveling, this can mean the phone connects to a foreign operator with higher roaming fees, even when a cheaper network is available with similar coverage a short distance away.
Manual selection removes that guesswork. Go to Settings ➔ Connections ➔ Mobile networks ➔ Network operators, then turn off Select automatically. The phone scans and lists every Available network it can reach, and you tap the one you want to use.
Keep in mind the connection stays fixed to that operator until you switch Select automatically back on. If the manually chosen network loses signal, the phone will not fall back to another provider on its own, so you may end up without service until you reconnect manually or re-enable automatic mode.
Manual selection makes most sense for short stays near a border or a single trip abroad, where you know which local operator is cheapest. For frequent travel across different regions, automatic mode is usually more practical since it avoids constant manual switching.