diff --git a/hugr-core/src/types/serialize.rs b/hugr-core/src/types/serialize.rs
index 9d7673184..2f1daf22c 100644
--- a/hugr-core/src/types/serialize.rs
+++ b/hugr-core/src/types/serialize.rs
@@ -5,7 +5,6 @@ use super::custom::CustomType;
 use crate::extension::prelude::{qb_t, usize_t};
 use crate::extension::SignatureError;
 use crate::ops::AliasDecl;
-use crate::std_extensions::collections::array::array_type;
 
 #[derive(serde::Serialize, serde::Deserialize, Clone, Debug)]
 #[serde(tag = "t")]
@@ -14,7 +13,6 @@ pub(super) enum SerSimpleType {
     I,
     G(Box<FuncValueType>),
     Sum(SumType),
-    Array { inner: Box<SerSimpleType>, len: u64 },
     Opaque(CustomType),
     Alias(AliasDecl),
     V { i: usize, b: TypeBound },
@@ -51,9 +49,6 @@ impl<RV: MaybeRV> TryFrom<SerSimpleType> for TypeBase<RV> {
             SerSimpleType::I => usize_t().into_(),
             SerSimpleType::G(sig) => TypeBase::new_function(*sig),
             SerSimpleType::Sum(st) => st.into(),
-            SerSimpleType::Array { inner, len } => {
-                array_type(len, (*inner).try_into().unwrap()).into_()
-            }
             SerSimpleType::Opaque(o) => TypeBase::new_extension(o),
             SerSimpleType::Alias(a) => TypeBase::new_alias(a),
             SerSimpleType::V { i, b } => TypeBase::new_var_use(i, b),
diff --git a/specification/schema/hugr_schema_live.json b/specification/schema/hugr_schema_live.json
index 5df9aa9fb..8037e513d 100644
--- a/specification/schema/hugr_schema_live.json
+++ b/specification/schema/hugr_schema_live.json
@@ -92,34 +92,6 @@
             "title": "AliasDefn",
             "type": "object"
         },
-        "Array": {
-            "additionalProperties": true,
-            "description": "Known size array whose elements are of the same type.",
-            "properties": {
-                "t": {
-                    "const": "Array",
-                    "default": "Array",
-                    "enum": [
-                        "Array"
-                    ],
-                    "title": "T",
-                    "type": "string"
-                },
-                "inner": {
-                    "$ref": "#/$defs/Type"
-                },
-                "len": {
-                    "title": "Len",
-                    "type": "integer"
-                }
-            },
-            "required": [
-                "inner",
-                "len"
-            ],
-            "title": "Array",
-            "type": "object"
-        },
         "BoundedNatArg": {
             "additionalProperties": true,
             "properties": {
@@ -1794,7 +1766,6 @@
             "discriminator": {
                 "mapping": {
                     "Alias": "#/$defs/Alias",
-                    "Array": "#/$defs/Array",
                     "G": "#/$defs/FunctionType",
                     "I": "#/$defs/USize",
                     "Opaque": "#/$defs/Opaque",
@@ -1821,9 +1792,6 @@
                 {
                     "$ref": "#/$defs/FunctionType"
                 },
-                {
-                    "$ref": "#/$defs/Array"
-                },
                 {
                     "$ref": "#/$defs/SumType"
                 },
diff --git a/specification/schema/hugr_schema_strict_live.json b/specification/schema/hugr_schema_strict_live.json
index 9a28e6397..7d7b1342a 100644
--- a/specification/schema/hugr_schema_strict_live.json
+++ b/specification/schema/hugr_schema_strict_live.json
@@ -92,34 +92,6 @@
             "title": "AliasDefn",
             "type": "object"
         },
-        "Array": {
-            "additionalProperties": false,
-            "description": "Known size array whose elements are of the same type.",
-            "properties": {
-                "t": {
-                    "const": "Array",
-                    "default": "Array",
-                    "enum": [
-                        "Array"
-                    ],
-                    "title": "T",
-                    "type": "string"
-                },
-                "inner": {
-                    "$ref": "#/$defs/Type"
-                },
-                "len": {
-                    "title": "Len",
-                    "type": "integer"
-                }
-            },
-            "required": [
-                "inner",
-                "len"
-            ],
-            "title": "Array",
-            "type": "object"
-        },
         "BoundedNatArg": {
             "additionalProperties": false,
             "properties": {
@@ -1794,7 +1766,6 @@
             "discriminator": {
                 "mapping": {
                     "Alias": "#/$defs/Alias",
-                    "Array": "#/$defs/Array",
                     "G": "#/$defs/FunctionType",
                     "I": "#/$defs/USize",
                     "Opaque": "#/$defs/Opaque",
@@ -1821,9 +1792,6 @@
                 {
                     "$ref": "#/$defs/FunctionType"
                 },
-                {
-                    "$ref": "#/$defs/Array"
-                },
                 {
                     "$ref": "#/$defs/SumType"
                 },
diff --git a/specification/schema/testing_hugr_schema_live.json b/specification/schema/testing_hugr_schema_live.json
index c7e80644e..9e86bff7c 100644
--- a/specification/schema/testing_hugr_schema_live.json
+++ b/specification/schema/testing_hugr_schema_live.json
@@ -92,34 +92,6 @@
             "title": "AliasDefn",
             "type": "object"
         },
-        "Array": {
-            "additionalProperties": true,
-            "description": "Known size array whose elements are of the same type.",
-            "properties": {
-                "t": {
-                    "const": "Array",
-                    "default": "Array",
-                    "enum": [
-                        "Array"
-                    ],
-                    "title": "T",
-                    "type": "string"
-                },
-                "inner": {
-                    "$ref": "#/$defs/Type"
-                },
-                "len": {
-                    "title": "Len",
-                    "type": "integer"
-                }
-            },
-            "required": [
-                "inner",
-                "len"
-            ],
-            "title": "Array",
-            "type": "object"
-        },
         "BoundedNatArg": {
             "additionalProperties": true,
             "properties": {
@@ -1872,7 +1844,6 @@
             "discriminator": {
                 "mapping": {
                     "Alias": "#/$defs/Alias",
-                    "Array": "#/$defs/Array",
                     "G": "#/$defs/FunctionType",
                     "I": "#/$defs/USize",
                     "Opaque": "#/$defs/Opaque",
@@ -1899,9 +1870,6 @@
                 {
                     "$ref": "#/$defs/FunctionType"
                 },
-                {
-                    "$ref": "#/$defs/Array"
-                },
                 {
                     "$ref": "#/$defs/SumType"
                 },
diff --git a/specification/schema/testing_hugr_schema_strict_live.json b/specification/schema/testing_hugr_schema_strict_live.json
index 08e37e707..88ee9d4dd 100644
--- a/specification/schema/testing_hugr_schema_strict_live.json
+++ b/specification/schema/testing_hugr_schema_strict_live.json
@@ -92,34 +92,6 @@
             "title": "AliasDefn",
             "type": "object"
         },
-        "Array": {
-            "additionalProperties": false,
-            "description": "Known size array whose elements are of the same type.",
-            "properties": {
-                "t": {
-                    "const": "Array",
-                    "default": "Array",
-                    "enum": [
-                        "Array"
-                    ],
-                    "title": "T",
-                    "type": "string"
-                },
-                "inner": {
-                    "$ref": "#/$defs/Type"
-                },
-                "len": {
-                    "title": "Len",
-                    "type": "integer"
-                }
-            },
-            "required": [
-                "inner",
-                "len"
-            ],
-            "title": "Array",
-            "type": "object"
-        },
         "BoundedNatArg": {
             "additionalProperties": false,
             "properties": {
@@ -1872,7 +1844,6 @@
             "discriminator": {
                 "mapping": {
                     "Alias": "#/$defs/Alias",
-                    "Array": "#/$defs/Array",
                     "G": "#/$defs/FunctionType",
                     "I": "#/$defs/USize",
                     "Opaque": "#/$defs/Opaque",
@@ -1899,9 +1870,6 @@
                 {
                     "$ref": "#/$defs/FunctionType"
                 },
-                {
-                    "$ref": "#/$defs/Array"
-                },
                 {
                     "$ref": "#/$defs/SumType"
                 },