diff --git a/.changes/20260813_120000_cardano-api_sebastian.nagel_stake_pool_bls_key.yml b/.changes/20260813_120000_cardano-api_sebastian.nagel_stake_pool_bls_key.yml
new file mode 100644
index 0000000000..8b44feff52
--- /dev/null
+++ b/.changes/20260813_120000_cardano-api_sebastian.nagel_stake_pool_bls_key.yml
@@ -0,0 +1,7 @@
+description: |
+  Added `stakePoolBlsKey :: Maybe Ledger.BlsKey` to `StakePoolParameters`, wired to the ledger's `sppBlsKey` in `toShelleyPoolParams`/`fromShelleyPoolParams`. This is a BLS voting key plus its proof of possession, registrable from the Dijkstra era onwards; `Nothing` for a pool that does not vote. Callers constructing `StakePoolParameters` need to set the new field. Also added `createBlsKeyRegistration :: SigningKey BlsKey -> Ledger.BlsKey`, which derives the verification key and proof of possession from a BLS signing key, and re-exported the ledger's `BlsKey` from `Cardano.Api.Ledger`.
+kind:
+  - feature
+  - breaking
+pr: 0
+project: cardano-api
diff --git a/cardano-api/cardano-api.cabal b/cardano-api/cardano-api.cabal
index e1ea28870c..078a4bef27 100644
--- a/cardano-api/cardano-api.cabal
+++ b/cardano-api/cardano-api.cabal
@@ -146,7 +146,7 @@ library
     cardano-ledger-binary >=1.6,
     cardano-ledger-byron >=1.2,
     cardano-ledger-conway >=1.19,
-    cardano-ledger-core >=1.20,
+    cardano-ledger-core >=1.22,
     cardano-ledger-dijkstra >=0.1,
     cardano-ledger-mary >=1.8,
     cardano-ledger-shelley >=1.16,
diff --git a/cardano-api/src/Cardano/Api/Certificate/Internal.hs b/cardano-api/src/Cardano/Api/Certificate/Internal.hs
index 54530aed14..d709deea98 100644
--- a/cardano-api/src/Cardano/Api/Certificate/Internal.hs
+++ b/cardano-api/src/Cardano/Api/Certificate/Internal.hs
@@ -50,6 +50,9 @@ data StakePoolParameters
   = StakePoolParameters
   { stakePoolId :: PoolId
   , stakePoolVRF :: Hash VrfKey
+  , stakePoolBlsKey :: Maybe Ledger.BlsKey
+  -- ^ The pool's BLS voting key and its proof of possession. Only registrable
+  -- from the Dijkstra era onwards; 'Nothing' for a pool that does not vote.
   , stakePoolCost :: L.Coin
   , stakePoolMargin :: Rational
   , stakePoolRewardAccount :: StakeAddress
@@ -91,6 +94,7 @@ toShelleyPoolParams
   StakePoolParameters
     { stakePoolId = StakePoolKeyHash poolkh
     , stakePoolVRF = VrfKeyHash vrfkh
+    , stakePoolBlsKey
     , stakePoolCost
     , stakePoolMargin
     , stakePoolRewardAccount
@@ -120,6 +124,7 @@ toShelleyPoolParams
       , Ledger.sppMetadata =
           toShelleyPoolMetadata
             <$> Ledger.maybeToStrictMaybe stakePoolMetadata
+      , Ledger.sppBlsKey = Ledger.maybeToStrictMaybe stakePoolBlsKey
       }
    where
     toShelleyStakePoolRelay :: StakePoolRelay -> Ledger.StakePoolRelay
@@ -172,10 +177,12 @@ fromShelleyPoolParams
     , Ledger.sppOwners
     , Ledger.sppRelays
     , Ledger.sppMetadata
+    , Ledger.sppBlsKey
     } =
     StakePoolParameters
       { stakePoolId = StakePoolKeyHash sppId
       , stakePoolVRF = VrfKeyHash (Ledger.fromVRFVerKeyHash sppVrf)
+      , stakePoolBlsKey = Ledger.strictMaybeToMaybe sppBlsKey
       , stakePoolCost = sppCost
       , stakePoolMargin = Ledger.unboundRational sppMargin
       , stakePoolRewardAccount = fromShelleyStakeAddr sppAccountAddress
diff --git a/cardano-api/src/Cardano/Api/Key.hs b/cardano-api/src/Cardano/Api/Key.hs
index e3a03ea7fb..4494d61494 100644
--- a/cardano-api/src/Cardano/Api/Key.hs
+++ b/cardano-api/src/Cardano/Api/Key.hs
@@ -75,6 +75,7 @@ module Cardano.Api.Key
   , BlsPossessionProof
   , blsPossessionProof
   , createBlsPossessionProof
+  , createBlsKeyRegistration
 
     -- ** Type proxy
   , HasTypeProxy (..)
diff --git a/cardano-api/src/Cardano/Api/Key/Internal/Leios.hs b/cardano-api/src/Cardano/Api/Key/Internal/Leios.hs
index dd7cc93f48..4552993cdd 100644
--- a/cardano-api/src/Cardano/Api/Key/Internal/Leios.hs
+++ b/cardano-api/src/Cardano/Api/Key/Internal/Leios.hs
@@ -22,6 +22,9 @@ module Cardano.Api.Key.Internal.Leios
   , BlsPossessionProof
   , blsPossessionProof
   , createBlsPossessionProof
+
+    -- * Registration
+  , createBlsKeyRegistration
   )
 where
 
@@ -40,6 +43,9 @@ import Cardano.Crypto.DSIGN.BLS12381 qualified as Crypto
 import Cardano.Crypto.DSIGN.Class qualified as Crypto
 import Cardano.Crypto.Hash.Class qualified as Crypto
 import Cardano.Ledger.Hashes (HASH)
+-- Qualified: the ledger's 'BlsKey' record and its 'blsPossessionProof' field
+-- both clash with names this module already defines.
+import Cardano.Ledger.State qualified as Ledger
 
 import Data.ByteString (ByteString)
 import Data.Either.Combinators (maybeToRight)
@@ -216,3 +222,15 @@ instance HasTextEnvelope BlsPossessionProof where
 
   textEnvelopeDefaultDescr :: BlsPossessionProof -> TextEnvelopeDescr
   textEnvelopeDefaultDescr _ = "BLS12-381 possession proof"
+
+-- | Derive everything a stake pool has to register for the voting scheme: its
+-- BLS verification key plus a proof of possession for it.
+createBlsKeyRegistration :: SigningKey BlsKey -> Ledger.BlsKey
+createBlsKeyRegistration skey =
+  Ledger.BlsKey
+    { Ledger.blsPubKey = vkey
+    , Ledger.blsPossessionProof = proof
+    }
+ where
+  BlsVerificationKey vkey = getVerificationKey skey
+  BlsPossessionProof proof = createBlsPossessionProof skey
diff --git a/cardano-api/src/Cardano/Api/Ledger/Internal/Reexport.hs b/cardano-api/src/Cardano/Api/Ledger/Internal/Reexport.hs
index 2b6ce58c43..b38d4fb98f 100644
--- a/cardano-api/src/Cardano/Api/Ledger/Internal/Reexport.hs
+++ b/cardano-api/src/Cardano/Api/Ledger/Internal/Reexport.hs
@@ -19,6 +19,7 @@ module Cardano.Api.Ledger.Internal.Reexport
   , fromVRFVerKeyHash
   , toVRFVerKeyHash
   , StakePoolParams (..)
+  , BlsKey (..)
   , HasKeyRole
   , MIRPot (..)
   , MIRTarget (..)
@@ -414,7 +415,8 @@ import Cardano.Ledger.Shelley.TxCert
   , ShelleyTxCert (..)
   )
 import Cardano.Ledger.State
-  ( PoolMetadata (..)
+  ( BlsKey (..)
+  , PoolMetadata (..)
   , ScriptsNeeded
   , StakePoolParams (..)
   , StakePoolRelay (..)