Miners choose transactions by feerate. If fees rise after you send, a low-fee transaction can wait in the mempool for a long time.
First: your coins are not lost
Until it confirms, the transaction is just waiting. If it is eventually dropped from mempools, the coins remain where they were.
Option 1: Replace-by-Fee (rbf)
- The sender creates a new version of the transaction with a higher fee, spending the same inputs.
- BIP125 defined opt-in signalling. Since Bitcoin Core 28.0, nodes accept replacements by default even without the signal (full RBF).
- Many wallets show a "bump fee" button.
Option 2: Child-Pays-For-Parent (cpfp)
- The receiver (or the sender, via the change) spends an output of the stuck transaction with a high fee.
- Miners take both together, because the combined feerate is attractive.
- Useful when you are the receiver and cannot change the original.
Newer tools
Bitcoin Core 28.0 added package relay for one parent and one child, and TRUC transactions (version 3), mainly to make fee bumping more reliable for Lightning and other protocols.
Avoid it next time
- Check current fee levels before sending.
- Use a wallet that supports RBF and keeps change you can use for CPFP.
- Do not send a payment you cannot bump when time matters.