diff --git a/.changes/20260514_cardano_api_remove_legacy_txout_from_compat_and_experimental.yml b/.changes/20260514_cardano_api_remove_legacy_txout_from_compat_and_experimental.yml
new file mode 100644
index 0000000000..9b06019656
--- /dev/null
+++ b/.changes/20260514_cardano_api_remove_legacy_txout_from_compat_and_experimental.yml
@@ -0,0 +1,20 @@
+project: cardano-api
+pr: 1209
+kind:
+  - breaking
+description: |
+  Remove legacy `TxOut ctx era` from the Compatible and Experimental APIs.
+
+  `createCompatibleTx` now takes `[Exp.TxOut (ShelleyLedgerEra era)]` plus an explicit `Map L.DataHash (L.Data (ShelleyLedgerEra era))` for supplemental datums, mirroring how it already takes `Exp.TxCertificates` / `Exp.TxVotingProcedures` / `Exp.TxProposalProcedures`. The legacy `TxOut CtxTx era` bundled supplemental datums inside outputs; `Exp.TxOut` only carries the datum hash (the full datum lives in the witness set), so callers now thread them in explicitly.
+
+  Deletes the legacy bridge helpers re-exported from `Cardano.Api.Experimental.Tx`:
+
+  - `fromLegacyTxOut`
+  - `legacyDatumToDatum`
+  - `supplementalDatumFromLegacy`
+  - `toLedgerDatum`
+  - `DatumDecodingError`
+
+  These existed solely to convert legacy `TxOut CtxTx era` / `TxOutDatum CtxTx era` values into the experimental world. With the Compatible API no longer accepting the legacy type, they had no remaining in-repo callers. They are not re-exported from top-level `Cardano.Api`.
+
+  The legacy `TxOut ctx era` type itself is unchanged — `UTxO`, `Tx` body construction, fee/balancing, `LedgerState`, and Byron all still depend on it.
diff --git a/cardano-api/src/Cardano/Api/Compatible/Tx.hs b/cardano-api/src/Cardano/Api/Compatible/Tx.hs
index d95d684530..16c24eb9ef 100644
--- a/cardano-api/src/Cardano/Api/Compatible/Tx.hs
+++ b/cardano-api/src/Cardano/Api/Compatible/Tx.hs
@@ -37,6 +37,7 @@ import Cardano.Ledger.Alonzo.TxWits qualified as Alonzo
 import Cardano.Ledger.Api qualified as L
 import Cardano.Ledger.Core qualified as L
 
+import Data.Map.Strict (Map)
 import Data.Map.Strict qualified as Map
 import Data.Maybe
 import Data.Maybe.Strict
@@ -44,7 +45,6 @@ import Data.Monoid
 import Data.OSet.Strict (OSet)
 import Data.Sequence.Strict qualified as Seq
 import GHC.Exts (IsList (..))
-import GHC.Stack
 import Lens.Micro hiding (ix)
 
 data AnyProtocolUpdate era where
@@ -72,14 +72,19 @@ createCompatibleTx
   :: forall era
    . ShelleyBasedEra era
   -> [TxIn]
-  -> [TxOut CtxTx era]
+  -> [Exp.TxOut (ShelleyLedgerEra era)]
+  -> Map L.DataHash (L.Data (ShelleyLedgerEra era))
+  -- ^ Supplemental datums to include in the witness set. Use 'mempty' if
+  -- none are required. The legacy 'TxOut CtxTx era' bundled supplemental
+  -- datums inside outputs; 'Exp.TxOut' only carries the datum hash, so
+  -- callers thread the full datum bodies in here explicitly.
   -> Lovelace
   -- ^ Fee
   -> AnyProtocolUpdate era
   -> AnyVote era
   -> Exp.TxCertificates (ShelleyLedgerEra era)
   -> Either ProtocolParametersConversionError (Tx era)
-createCompatibleTx sbe ins outs txFee' anyProtocolUpdate anyVote txCertificates' =
+createCompatibleTx sbe ins outs extraDatums txFee' anyProtocolUpdate anyVote txCertificates' =
   shelleyBasedEraConstraints sbe $ do
     (updateTxBody, extraScriptWitnesses) <-
       case anyProtocolUpdate of
@@ -186,7 +191,7 @@ createCompatibleTx sbe ins outs txFee' anyProtocolUpdate anyVote txCertificates'
       [ monoidForEraInEon
           era
           ( \aeo -> alonzoEraOnwardsConstraints aeo $ Endo $ do
-              let sData = convScriptData' sbe outs scriptWitnesses
+              let sData = convScriptData' sbe extraDatums scriptWitnesses
               let (datums, redeemers) = case sData of
                     TxBodyScriptData _ ds rs -> (ds, rs)
                     TxBodyNoScriptData -> (mempty, L.Redeemers mempty)
@@ -223,25 +228,16 @@ convCertificates (Exp.TxCertificates cs) =
 
 convScriptData'
   :: ShelleyBasedEra era
-  -> [TxOut CtxTx era]
+  -> Map L.DataHash (L.Data (ShelleyLedgerEra era))
   -> [(ScriptWitnessIndex, AnyWitness (ShelleyLedgerEra era))]
   -> TxBodyScriptData era
-convScriptData' sbe txOuts' scriptWitnesses =
+convScriptData' sbe extraDatums scriptWitnesses =
   caseShelleyToMaryOrAlonzoEraOnwards
     (const TxBodyNoScriptData)
     ( \w ->
         let redeemers = getAnyPlutusScriptWitnessRedeemerPointerMap w scriptWitnesses
-
             datums = mconcat [getAnyWitnessScriptData wit | (_, wit) <- scriptWitnesses]
-
-            supplementalDatums =
-              let ds = [d | TxOut _ _ (TxOutSupplementalDatum _ d) _ <- txOuts']
-               in Alonzo.TxDats $
-                    fromList
-                      [ (L.hashData d', d')
-                      | d <- ds
-                      , let d' = toAlonzoData d
-                      ]
+            supplementalDatums = alonzoEraOnwardsConstraints w $ Alonzo.TxDats extraDatums
          in TxBodyScriptData w (datums <> supplementalDatums) redeemers
     )
     sbe
@@ -268,17 +264,16 @@ getAnyPlutusScriptWitnessRedeemerPointerMap w wits =
         ]
 
 createCommonTxBody
-  :: HasCallStack
-  => ShelleyBasedEra era
+  :: ShelleyBasedEra era
   -> [TxIn]
-  -> [TxOut ctx era]
+  -> [Exp.TxOut (ShelleyLedgerEra era)]
   -> Lovelace
   -> L.TxBody L.TopTx (ShelleyLedgerEra era)
 createCommonTxBody era ins outs txFee' =
-  let txIns' = map toShelleyTxIn ins
-      txOuts' = map (toShelleyTxOutAny era) outs
-   in shelleyBasedEraConstraints era $
-        L.mkBasicTxBody
+  shelleyBasedEraConstraints era $
+    let txIns' = map toShelleyTxIn ins
+        txOuts' = map (\(Exp.TxOut o) -> o) outs
+     in L.mkBasicTxBody
           & L.inputsTxBodyL
             .~ fromList txIns'
           & L.outputsTxBodyL
diff --git a/cardano-api/src/Cardano/Api/Experimental/Tx.hs b/cardano-api/src/Cardano/Api/Experimental/Tx.hs
index 2e8d487520..779934ad1f 100644
--- a/cardano-api/src/Cardano/Api/Experimental/Tx.hs
+++ b/cardano-api/src/Cardano/Api/Experimental/Tx.hs
@@ -158,12 +158,6 @@ module Cardano.Api.Experimental.Tx
   , setTxVotingProcedures
   , setTxWithdrawals
 
-    -- * Legacy Conversions
-  , DatumDecodingError (..)
-  , legacyDatumToDatum
-  , fromLegacyTxOut
-  , supplementalDatumFromLegacy
-
     -- * TxBodyContent sub type
   , TxCertificates (..)
   , TxMintValue (..)
diff --git a/cardano-api/src/Cardano/Api/Experimental/Tx/Internal/BodyContent/New.hs b/cardano-api/src/Cardano/Api/Experimental/Tx/Internal/BodyContent/New.hs
index 7ef0d706a2..281a68ea50 100644
--- a/cardano-api/src/Cardano/Api/Experimental/Tx/Internal/BodyContent/New.hs
+++ b/cardano-api/src/Cardano/Api/Experimental/Tx/Internal/BodyContent/New.hs
@@ -69,12 +69,6 @@ module Cardano.Api.Experimental.Tx.Internal.BodyContent.New
   , extractWitnessableWithdrawals
   , extractWitnessableVotes
   , extractWitnessableProposals
-
-    -- * Legacy conversions
-  , DatumDecodingError (..)
-  , legacyDatumToDatum
-  , fromLegacyTxOut
-  , supplementalDatumFromLegacy
   )
 where
 
@@ -117,7 +111,6 @@ import Cardano.Api.Plutus.Internal.Script
   )
 import Cardano.Api.Plutus.Internal.Script qualified as OldScript
 import Cardano.Api.Plutus.Internal.ScriptData qualified as Api
-import Cardano.Api.Pretty
 import Cardano.Api.Serialise.Cbor (serialiseToCBOR)
 import Cardano.Api.Tx.Internal.Body
   ( CtxTx
@@ -126,7 +119,6 @@ import Cardano.Api.Tx.Internal.Body
   , toShelleyTxIn
   , toShelleyWithdrawal
   )
-import Cardano.Api.Tx.Internal.Output qualified as OldApi
 import Cardano.Api.Tx.Internal.Sign
 import Cardano.Api.Tx.Internal.TxMetadata
 import Cardano.Api.Value.Internal
@@ -153,7 +145,6 @@ import Control.Monad
 import Data.Aeson (ToJSON (..), (.=))
 import Data.Aeson qualified as Aeson
 import Data.ByteString.Base16 qualified as Base16
-import Data.ByteString.Short qualified as SBS
 import Data.Functor
 import Data.List qualified as List
 import Data.Map.Ordered.Strict (OMap)
@@ -169,7 +160,6 @@ import Data.Set qualified as Set
 import Data.Text.Encoding qualified as Text
 import Data.Typeable (cast)
 import GHC.Exts (IsList (..))
-import GHC.Stack (HasCallStack)
 import Lens.Micro
 
 -- | Error that can occur when constructing an unsigned transaction.
@@ -521,63 +511,6 @@ extractDatumsAndHashes TxOutDatumHash{} = Nothing
 extractDatumsAndHashes (TxOutSupplementalDatum h d) = Just (h, d)
 extractDatumsAndHashes (TxOutDatumInline h d) = Just (h, d)
 
-hashableScriptDatumToDatumAndHash :: L.Era era => Api.HashableScriptData -> (L.DataHash, L.Data era)
-hashableScriptDatumToDatumAndHash sd =
-  (Api.unScriptDataHash $ Api.hashScriptDataBytes sd, Api.toAlonzoData sd)
-
-legacyDatumToDatum
-  :: forall era. IsEra era => OldApi.TxOutDatum CtxTx era -> Maybe (Datum CtxTx (LedgerEra era))
-legacyDatumToDatum (OldApi.TxOutDatumHash _ h) = Just (TxOutDatumHash $ Api.unScriptDataHash h)
-legacyDatumToDatum (OldApi.TxOutSupplementalDatum _ hd) = do
-  let (hash, d) = obtainCommonConstraints (useEra @era) $ hashableScriptDatumToDatumAndHash hd
-  Just (TxOutSupplementalDatum hash d)
-legacyDatumToDatum (OldApi.TxOutDatumInline _ hd) = do
-  let (hash, d) = obtainCommonConstraints (useEra @era) $ hashableScriptDatumToDatumAndHash hd
-  Just (TxOutDatumInline hash d)
-legacyDatumToDatum OldApi.TxOutDatumNone = Nothing
-
-fromLegacyTxOut
-  :: forall era
-   . HasCallStack
-  => IsEra era
-  => OldApi.TxOut CtxTx era
-  -> Either DatumDecodingError (TxOut (LedgerEra era), Map L.DataHash (L.Data (LedgerEra era)))
-fromLegacyTxOut tOut@(OldApi.TxOut _ _ d _) = do
-  let o = OldApi.toShelleyTxOutAny (convert $ useEra @era) tOut
-  newDatum :: L.Datum (LedgerEra era) <- obtainCommonConstraints (useEra @era) $ toLedgerDatum d
-  let txOut = obtainCommonConstraints (useEra @era) $ TxOut $ o & L.datumTxOutL .~ newDatum
-      suppDats = obtainCommonConstraints (useEra @era) $ supplementalDatumFromLegacy d
-  return (txOut, suppDats)
-
--- | Extract supplemental datum data from a legacy 'TxOutDatum'.
--- Returns 'mempty' for non-supplemental datums.
-supplementalDatumFromLegacy
-  :: L.Era (LedgerEra era)
-  => OldApi.TxOutDatum CtxTx era
-  -> Map L.DataHash (L.Data (LedgerEra era))
-supplementalDatumFromLegacy (OldApi.TxOutSupplementalDatum _ h) =
-  let ledgerData = Api.toAlonzoData h
-   in fromList [(L.hashData ledgerData, ledgerData)]
-supplementalDatumFromLegacy _ = mempty
-
-newtype DatumDecodingError = DatumDecodingError String
-  deriving (Show, Eq)
-
-instance Error DatumDecodingError where
-  prettyError (DatumDecodingError msg) = "Datum decoding error: " <> pshow msg
-
-toLedgerDatum
-  :: L.Era (LedgerEra era)
-  => OldApi.TxOutDatum CtxTx era -> Either DatumDecodingError (L.Datum (LedgerEra era))
-toLedgerDatum OldApi.TxOutDatumNone = Right L.NoDatum
-toLedgerDatum (OldApi.TxOutDatumHash _ (Api.ScriptDataHash h)) = Right $ L.DatumHash h
-toLedgerDatum (OldApi.TxOutSupplementalDatum _ h) =
-  Right $ L.DatumHash (Api.unScriptDataHash $ Api.hashScriptDataBytes h)
-toLedgerDatum (OldApi.TxOutDatumInline _ h) =
-  case L.makeBinaryData $ SBS.toShort $ Api.getOriginalScriptDataBytes h of
-    Left e -> Left $ DatumDecodingError e
-    Right bd -> Right $ L.Datum bd
-
 data TxInsReference era = TxInsReference [TxIn] (Set (Datum CtxTx era))
 
 newtype TxTotalCollateral = TxTotalCollateral {unTxTotalCollateral :: L.Coin}
diff --git a/cardano-api/test/cardano-api-test/Test/Cardano/Api/Experimental/Fee.hs b/cardano-api/test/cardano-api-test/Test/Cardano/Api/Experimental/Fee.hs
index 6c6d57027c..398ca83c96 100644
--- a/cardano-api/test/cardano-api-test/Test/Cardano/Api/Experimental/Fee.hs
+++ b/cardano-api/test/cardano-api-test/Test/Cardano/Api/Experimental/Fee.hs
@@ -775,7 +775,7 @@ prop_createCompatibleTx_preserves_all_certs = H.property $ do
   let sbe = convert Exp.ConwayEra
       inputCerts = Exp.mkTxCertificates Exp.ConwayEra allCerts
   Api.ShelleyTx _ ledgerTx <-
-    H.evalEither $ createCompatibleTx sbe [] [] 0 (NoPParamsUpdate sbe) NoVotes inputCerts
+    H.evalEither $ createCompatibleTx sbe [] [] mempty 0 (NoPParamsUpdate sbe) NoVotes inputCerts
   let bodyCerts = ledgerTx ^. L.bodyTxL . L.certsTxBodyL
   Seq.length bodyCerts H.=== expectedCount