How to Enable Call Waiting on Oppo Phones

Call waiting lets you hear an alert when someone calls while you are already on the phone, so you can hold, switch or decline. On Oppo phones such as the A3s and A5, the switch sits in the phone's call settings. The service itself is provided by your mobile carrier, not by the handset.

Before you start

• An active SIM card from a carrier that offers call waiting on your plan. Some prepaid or business plans do not include it.
• Mobile network coverage, with airplane mode turned off. The phone has to reach the carrier to change the setting, so it cannot be switched offline.
• If you use two SIM cards, decide which one needs call waiting. The setting applies to each SIM separately.
• Check whether call forwarding "when busy" is turned on. If it is, busy calls may go to voicemail or another number instead of producing a waiting alert.

Menu names and locations vary between ColorOS versions. The Oppo A3s runs an older release than recent models. The A5 name covers several generations, so your screens may differ from the wording below. If a label does not match, search for "call waiting" in the Settings app.

Step-by-step instructions

Turn it on from the phone settings

• Open the Phone (dialer) app.
• Tap the three-dot menu or the settings icon and choose Settings. On some versions, the call options are instead in the Settings app, under an entry such as Call settings, Phone or System apps > Phone.
• If two SIMs are inserted, choose the SIM you want to configure.
• Look for Call waiting. It may be on the main call settings screen or inside a submenu such as Additional settings or Supplementary services.
• Turn on the Call waiting switch. The phone contacts the network, which can take a few seconds. Wait until the switch stays on without an error message.
• To undo the change later, return to the same screen and turn the switch off.

Use a network code instead

Many GSM carriers accept standard service codes typed into the dialer and sent with the call button. Use *43# to activate call waiting, #43# to deactivate it, and *#43# to check its status. Whether these codes work depends on the carrier, so if you get an error or no response, use the menu method or ask your provider.

Check the output

First, check the status. Reopen the call settings and confirm the switch is still on, or dial *#43# and read the carrier's reply. Then make a real test: start a call, and ask someone to ring your number from another phone during that call. With call waiting active, you should hear a short tone, and the incoming call should appear on screen with options to answer, hold or decline. If the second caller hears a busy signal or reaches voicemail instead, the service is not active on the network side, even if the switch looks enabled.

Features beyond the basic alert depend on the carrier, such as merging calls into a conference or swapping between them. The handset setting alone does not guarantee them.

Common problems and next steps

• The switch turns itself off, or you see a network or SIM error: confirm you have signal and the SIM is active, then try again. If the error repeats, the carrier may not have the service enabled on your line. Contact them to add or provision it.
• Can't find the option on an Oppo A5 or A3s: open the Settings app and search for "call waiting", or check each SIM's call settings separately. If it still does not appear, use the *43# code.
• Calls go to voicemail when you are busy: turn off call forwarding for the busy condition in the same call settings area, then test again.
• No alert for calls to your second SIM: on dual-SIM phones that keep both SIMs on standby, a call on one SIM usually prevents the other from receiving calls. Call waiting works within the same SIM, so a call to the second SIM generally cannot ring through.
• The setting fails only with VoLTE or Wi-Fi calling enabled: some carriers manage call waiting differently over these services. Ask your carrier how call waiting is supported on your plan rather than changing network modes at random.