diff --git a/src/main/java/org/springframework/data/r2dbc/convert/MappingR2dbcConverter.java b/src/main/java/org/springframework/data/r2dbc/convert/MappingR2dbcConverter.java
index d8680ae..5e05c78 100644
--- a/src/main/java/org/springframework/data/r2dbc/convert/MappingR2dbcConverter.java
+++ b/src/main/java/org/springframework/data/r2dbc/convert/MappingR2dbcConverter.java
@@ -31,6 +31,7 @@ import org.springframework.core.CollectionFactory;
 import org.springframework.core.convert.ConversionService;
 import org.springframework.dao.InvalidDataAccessApiUsageException;
 import org.springframework.data.convert.CustomConversions;
+import org.springframework.data.mapping.IdentifierAccessor;
 import org.springframework.data.mapping.MappingException;
 import org.springframework.data.mapping.PersistentProperty;
 import org.springframework.data.mapping.PersistentPropertyAccessor;
@@ -370,7 +371,14 @@ public class MappingR2dbcConverter extends BasicRelationalConverter implements R
 				continue;
 			}
 
-			Object value = accessor.getProperty(property);
+			Object value;
+
+			if (property.isIdProperty()) {
+				IdentifierAccessor identifierAccessor = entity.getIdentifierAccessor(accessor.getBean());
+				value = identifierAccessor.getIdentifier();
+			} else {
+				value = accessor.getProperty(property);
+			}
 
 			if (value == null) {
 				writeNullInternal(sink, property);
@@ -600,6 +608,10 @@ public class MappingR2dbcConverter extends BasicRelationalConverter implements R
 		Class<?> userClass = ClassUtils.getUserClass(object);
 		RelationalPersistentEntity<?> entity = getMappingContext().getRequiredPersistentEntity(userClass);
 
+		if (!entity.hasIdProperty()) {
+			return (row, rowMetadata) -> object;
+		}
+
 		return (row, metadata) -> {
 
 			PersistentPropertyAccessor<?> propertyAccessor = entity.getPropertyAccessor(object);
diff --git a/src/main/java/org/springframework/data/r2dbc/core/R2dbcEntityTemplate.java b/src/main/java/org/springframework/data/r2dbc/core/R2dbcEntityTemplate.java
index f23fd9f..0f2c515 100644
--- a/src/main/java/org/springframework/data/r2dbc/core/R2dbcEntityTemplate.java
+++ b/src/main/java/org/springframework/data/r2dbc/core/R2dbcEntityTemplate.java
@@ -65,6 +65,7 @@ import org.springframework.data.relational.core.query.CriteriaDefinition;
 import org.springframework.data.relational.core.query.Query;
 import org.springframework.data.relational.core.query.Update;
 import org.springframework.data.relational.core.sql.Expression;
+import org.springframework.data.relational.core.sql.Expressions;
 import org.springframework.data.relational.core.sql.Functions;
 import org.springframework.data.relational.core.sql.SqlIdentifier;
 import org.springframework.data.relational.core.sql.Table;
@@ -322,7 +323,11 @@ public class R2dbcEntityTemplate implements R2dbcEntityOperations, BeanFactoryAw
 		StatementMapper.SelectSpec selectSpec = statementMapper //
 				.createSelect(tableName) //
 				.doWithTable((table, spec) -> {
-					return spec.withProjection(Functions.count(table.column(entity.getRequiredIdProperty().getColumnName())));
+
+					Expression countExpression = entity.hasIdProperty()
+							? table.column(entity.getRequiredIdProperty().getColumnName())
+							: Expressions.asterisk();
+					return spec.withProjection(Functions.count(countExpression));
 				});
 
 		Optional<CriteriaDefinition> criteria = query.getCriteria();
@@ -834,6 +839,7 @@ public class R2dbcEntityTemplate implements R2dbcEntityOperations, BeanFactoryAw
 	}
 
 	private <T> Query getByIdQuery(T entity, RelationalPersistentEntity<?> persistentEntity) {
+
 		if (!persistentEntity.hasIdProperty()) {
 			throw new MappingException("No id property found for object of type " + persistentEntity.getType() + "!");
 		}
diff --git a/src/main/java/org/springframework/data/r2dbc/repository/query/R2dbcQueryCreator.java b/src/main/java/org/springframework/data/r2dbc/repository/query/R2dbcQueryCreator.java
index 6164f09..3abc8c2 100644
--- a/src/main/java/org/springframework/data/r2dbc/repository/query/R2dbcQueryCreator.java
+++ b/src/main/java/org/springframework/data/r2dbc/repository/query/R2dbcQueryCreator.java
@@ -29,6 +29,7 @@ import org.springframework.data.relational.core.mapping.RelationalPersistentProp
 import org.springframework.data.relational.core.query.Criteria;
 import org.springframework.data.relational.core.sql.Column;
 import org.springframework.data.relational.core.sql.Expression;
+import org.springframework.data.relational.core.sql.Expressions;
 import org.springframework.data.relational.core.sql.Functions;
 import org.springframework.data.relational.core.sql.SqlIdentifier;
 import org.springframework.data.relational.core.sql.Table;
@@ -164,8 +165,11 @@ class R2dbcQueryCreator extends RelationalQueryCreator<PreparedOperation<?>> {
 				.collect(Collectors.toList());
 		} else if (tree.isCountProjection()) {
 
-			SqlIdentifier idColumn = entityMetadata.getTableEntity().getRequiredIdProperty().getColumnName();
-			expressions = Collections.singletonList(Functions.count(table.column(idColumn)));
+			Expression countExpression = entityMetadata.getTableEntity().hasIdProperty()
+					? table.column(entityMetadata.getTableEntity().getRequiredIdProperty().getColumnName())
+					: Expressions.asterisk();
+
+			expressions = Collections.singletonList(Functions.count(countExpression));
 		} else {
 			expressions = dataAccessStrategy.getAllColumns(entityToRead).stream()
 				.map(table::column)
diff --git a/src/test/java/org/springframework/data/r2dbc/convert/MappingR2dbcConverterUnitTests.java b/src/test/java/org/springframework/data/r2dbc/convert/MappingR2dbcConverterUnitTests.java
index ef253b2..05d7f59 100644
--- a/src/test/java/org/springframework/data/r2dbc/convert/MappingR2dbcConverterUnitTests.java
+++ b/src/test/java/org/springframework/data/r2dbc/convert/MappingR2dbcConverterUnitTests.java
@@ -43,6 +43,7 @@ import org.springframework.data.annotation.Id;
 import org.springframework.data.annotation.Transient;
 import org.springframework.data.convert.ReadingConverter;
 import org.springframework.data.convert.WritingConverter;
+import org.springframework.data.domain.Persistable;
 import org.springframework.data.r2dbc.dialect.PostgresDialect;
 import org.springframework.data.r2dbc.mapping.OutboundRow;
 import org.springframework.data.r2dbc.mapping.R2dbcMappingContext;
@@ -250,6 +251,18 @@ public class MappingR2dbcConverterUnitTests {
 		assertThat(result.person).isNull();
 	}
 
+	@Test // GH-711
+	void writeShouldObtainIdFromIdentifierAccessor() {
+
+		PersistableEntity entity = new PersistableEntity();
+		entity.id = null;
+
+		OutboundRow row = new OutboundRow();
+		converter.write(entity, row);
+
+		assertThat(row).containsEntry(SqlIdentifier.unquoted("id"), Parameter.from(42L));
+	}
+
 	@AllArgsConstructor
 	static class Person {
 		@Id String id;
@@ -406,4 +419,19 @@ public class MappingR2dbcConverterUnitTests {
 			this.name = name;
 		}
 	}
+
+	static class PersistableEntity implements Persistable<Long> {
+
+		@Id String id;
+
+		@Override
+		public Long getId() {
+			return 42L;
+		}
+
+		@Override
+		public boolean isNew() {
+			return false;
+		}
+	}
 }